time limit per test

memory limit per test

input

output

A string is called a k-string if it can be represented as k concatenated copies of some string. For example, the string "aabaabaabaab" is at the same time a 1-string, a 2-string and a 4-string, but it is not a 3-string, a 5-string, or a 6-string and so on. Obviously any string is a 1-string.

You are given a string s, consisting of lowercase English letters and a positive integer k. Your task is to reorder the letters in the string sin such a way that the resulting string is a k-string.

Input

The first input line contains integer k (1?≤?k?≤?1000). The second line contains s, all characters in s are lowercase English letters. The string length s satisfies the inequality 1?≤?|s|?≤?1000, where |s| is the length of string s.

Output

Rearrange the letters in string s in such a way that the result is a k-string. Print the result on a single output line. If there are multiple solutions, print any of them.

If the solution doesn't exist, print "-1" (without quotes).

Sample test(s)

input

2aazz

output

azaz

input

3abcabcabz

output

-1

解题思路：给一个串，问是否能由k个相同的串连接而成。

用STL里的map。扫一遍，分别记录每个字符的个数，在判断所有的字符是否是k的倍数，若不是，则输出-1；否则，遍历依次map，每个字符输出（总个数）/k个，然后重复k次即可。

AC代码：

#include #include #include #include #include #include #include #include