A8348. Luck is in Numbers
编程题
普及/提高-
知识点
题目描述
The first line contains the number of the ticket that consists of $k$ characters ( $k=2n,1<=n<=10^{5}$ ).
输入格式
Print the number of the sought ticket or "-1" (without the quotes) if no such ticket exists.
输出格式
无
输入输出样例
输入 #1
13
输出 #1
20
输入 #2
2345
输出 #2
2348
输入 #3
88
输出 #3
-1