{"trustable":false,"prependHtml":"\u003cstyle type\u003d\u0027text/css\u0027\u003e\n .input, .output {\n border: 1px solid #888888;\n }\n .output {\n margin-bottom: 1em;\n position: relative;\n top: -1px;\n }\n .output pre, .input pre {\n background-color: #EFEFEF;\n line-height: 1.25em;\n margin: 0;\n padding: 0.25em;\n }\n \u003c/style\u003e\n \u003clink rel\u003d\"stylesheet\" href\u003d\"//codeforces.org/s/96598/css/problem-statement.css\" type\u003d\"text/css\" /\u003e\u003cscript\u003e window.katexOptions \u003d { disable: true }; \u003c/script\u003e\n\u003cscript type\u003d\"text/x-mathjax-config\"\u003e\n MathJax.Hub.Config({\n tex2jax: {\n inlineMath: [[\u0027$$$\u0027,\u0027$$$\u0027], [\u0027$\u0027,\u0027$\u0027]],\n displayMath: [[\u0027$$$$$$\u0027,\u0027$$$$$$\u0027], [\u0027$$\u0027,\u0027$$\u0027]]\n }\n });\n\u003c/script\u003e\n\u003cscript type\u003d\"text/javascript\" async src\u003d\"https://mathjax.codeforces.org/MathJax.js?config\u003dTeX-AMS_HTML-full\"\u003e\u003c/script\u003e","sections":[{"title":"","value":{"format":"MD","content":"\u003cp\u003etoday, sister xiang you came to the laboratory with a large number of milk tea, but each cup of milk tea had a lowercase english letter on it, and the trouble-loving gollum knew that emperor yin hated \"a\", so he arranged these milk teas into n sequences and formed n strings.\u003c/p\u003e\n\n\u003cp\u003eOnce when Emperor Yin was playing a certain sound game, he accidentally typed an \"A\" evaluation, and since then, Emperor Yin has begun to hate the letter \"A\" (both upper and lower case). So Emperor Yin didn\u0027t want to drink milk tea with the letter \"A\", so he threw some milk tea with \"A\" in the sequence to the next group, and the rest of the milk tea formed Yin Fu String (all other letters except \"A\" are kept in the order in the original string).\u003c/p\u003e\n\n\u003cp\u003ebut fu ge\u0027s memory is very good, he wrote down the sequence before he threw away these \"a\" milk tea, because fu ge wrote it down, we call these sequences fu fu strings. so he and wang gongzi bought some milk tea and reformed the rich charm string.\u003c/p\u003e\n\n\u003cp\u003eSenior Kevin looked at the table and sorted it out, he put the milk tea sequence (rich charm string) bought by Fu Ge and Wang Gongzi in the front, and the milk tea sequence (Yin Fu string) processed by Emperor Yin was placed in the back and combined into a K character string,\u003c/p\u003e\n\n\u003cp\u003eThat is: K string \u003d rich string + Yin string\u003c/p\u003e\n\u003cp\u003eNow Senior Yueyue gives some K strings (which may be fake), so that Senior Xiang You can judge whether she can find a rich string that meets the conditions, and you can use this string to generate according to the definition of K string \u003d rich string + Yin string. (If the judgment is correct, the milk tea money will be reimbursed.)\u003c/p\u003e\n\n\u003cp\u003eso ask sister you for help and ask her to help her write a program to judge, output this rich charm string if it exists, and output \":(\" if it does not exist (without quotation marks).\u003c/p\u003e"}},{"title":"Input","value":{"format":"MD","content":"\u003cp\u003eThe first line contains a K string k (1 \u003c\u003d |k| \u003c\u003d 10^5), which is guaranteed to consist of only lowercase English letters\u003c/p\u003e"}},{"title":"Output","value":{"format":"MD","content":"\u003cp\u003eoutput a rich string s. if such a s does not exist, then output a line \":(\" (without quotation marks).\u003c/p\u003e"}},{"title":"Sample 1","value":{"format":"MD","content":"\u003ctable class\u003d\u0027vjudge_sample\u0027\u003e\n\u003cthead\u003e\n \u003ctr\u003e\n \u003cth\u003eInput\u003c/th\u003e\n \u003cth\u003eOutput\u003c/th\u003e\n \u003c/tr\u003e\n\u003c/thead\u003e\n\u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd\u003e\u003cpre\u003eaaaaa\n\u003c/pre\u003e\u003c/td\u003e\n \u003ctd\u003e\u003cpre\u003eaaaaa\n\u003c/pre\u003e\u003c/td\u003e\n \u003c/tr\u003e\n\u003c/tbody\u003e\n\u003c/table\u003e\n"}},{"title":"Sample 2","value":{"format":"MD","content":"\u003ctable class\u003d\u0027vjudge_sample\u0027\u003e\n\u003cthead\u003e\n \u003ctr\u003e\n \u003cth\u003eInput\u003c/th\u003e\n \u003cth\u003eOutput\u003c/th\u003e\n \u003c/tr\u003e\n\u003c/thead\u003e\n\u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd\u003e\u003cpre\u003eaacaababc\n\u003c/pre\u003e\u003c/td\u003e\n \u003ctd\u003e\u003cpre\u003e:(\n\u003c/pre\u003e\u003c/td\u003e\n \u003c/tr\u003e\n\u003c/tbody\u003e\n\u003c/table\u003e\n"}},{"title":"Sample 3","value":{"format":"MD","content":"\u003ctable class\u003d\u0027vjudge_sample\u0027\u003e\n\u003cthead\u003e\n \u003ctr\u003e\n \u003cth\u003eInput\u003c/th\u003e\n \u003cth\u003eOutput\u003c/th\u003e\n \u003c/tr\u003e\n\u003c/thead\u003e\n\u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd\u003e\u003cpre\u003eababacacbbcc\n\u003c/pre\u003e\u003c/td\u003e\n \u003ctd\u003e\u003cpre\u003eababacac\n\u003c/pre\u003e\u003c/td\u003e\n \u003c/tr\u003e\n\u003c/tbody\u003e\n\u003c/table\u003e\n"}},{"title":"Sample 4","value":{"format":"MD","content":"\u003ctable class\u003d\u0027vjudge_sample\u0027\u003e\n\u003cthead\u003e\n \u003ctr\u003e\n \u003cth\u003eInput\u003c/th\u003e\n \u003cth\u003eOutput\u003c/th\u003e\n \u003c/tr\u003e\n\u003c/thead\u003e\n\u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd\u003e\u003cpre\u003ebaba\n\u003c/pre\u003e\u003c/td\u003e\n \u003ctd\u003e\u003cpre\u003e:(\n\u003c/pre\u003e\u003c/td\u003e\n \u003c/tr\u003e\n\u003c/tbody\u003e\n\u003c/table\u003e\n"}},{"title":"Note","value":{"format":"MD","content":"\u003cp\u003ein the first example, rich character string \u003d \"\u003cspan class\u003d\"tex-font-style-tt\"\u003eaaaaa\u003c/span\u003e\", yin character string \u003d \"\u003cspan class\u003d\"tex-font-style-tt\"\u003e\u003c/span\u003e\".\u003c/p\u003e\n\u003cp\u003eIN THE SECOND EXAMPLE, NONE OF THE RICH STRINGS CAN GENERATE THE GIVEN K STRING\u003c/p\u003e\n\u003cp\u003eIIn the first example, rich string \u003d \"\u003cspan class\u003d\"tex-font-style-tt\"\u003eababacac\u003c/span\u003e\", Yin string \u003d \"\u003cspan class\u003d\"tex-font-style-tt\"\u003ebbcc\u003c/span\u003e\",and K string \u003d \"\u003cspan class\u003d\"tex-font-style-tt\"\u003eababacacbbcc\u003c/span\u003e\".\u003c/p\u003e"}}]}