2
aaab
 2
babac
 2
aaaaaabbbb
 1
aabaab
 2
aabbbbccccccdddddddd
 2
abba
 2
aaaazzzz
 250
cececececececececececececececececececececececececececececececececececececececececececececececececececececececececececececececececececececececececececececececececececececececececececececececececececececececececececececececececececececececececececececececececececececececececececececececececececececececececececececececececececececececececececececececececececececececececececececececececececececececececececececececececececececececececececececececececececececececececececececececececececececececececece
 3
aaaaaaaaacccdddddd
 2
aabaab
 1
aaaaa
 7
abacaba
 2
aaaabbbb
 5
aaaaa
 1
aaa
 2
aaazz
 3
aabaaaaabb
 2
aaaa
 2
aa
 3
bbbccc
 15
abaabbbcababaaaabaabbbcababaaaabaabbbcababaaaabaabbbcababaaaabaabbbcababaaaabaabbbcababaaaabaabbbcababaaaabaabbbcababaaaabaabbbcababaaaabaabbbcababaaaabaabbbcababaaaabaabbbcababaaaabaabbbcababaaaabaabbbcababaaaabaabbbcababaaa
 1
a
 2
bbaaaa
 2
aaaabb
 2
aabbbb
 2
aaaaaazz
 3
aaaaaaaaacccbbbbbb
 2
bbbbaa
 2
aaaazz
 2
aazzzz
 2
acaccc

-1
 -1
 aaabbaaabb aaaabb
 abbcccddddabbcccdddd abab
 aazzaazz cececececececececececececececececececececececececececececececececececececececececececececececececececececececececececececececececececececececececececececececececececececececececececececececececececececececececececececececececececececececececececececececececececececececececececececececececececececececececececececececececececececececececececececececececececececececececececececececececececececececececececececececececececececececececececececececececececececececececececececececececececececececececece
 aaacddaaacddaaacdd aabaab
 aaaaa
 -1
 aabbaabb
 aaaaa
 aaa
 -1
 -1
 aaaa
 aa
 bcbcbc
 aaaaaaaabbbbbbcaaaaaaaabbbbbbcaaaaaaaabbbbbbcaaaaaaaabbbbbbcaaaaaaaabbbbbbcaaaaaaaabbbbbbcaaaaaaaabbbbbbcaaaaaaaabbbbbbcaaaaaaaabbbbbbcaaaaaaaabbbbbbcaaaaaaaabbbbbbcaaaaaaaabbbbbbcaaaaaaaabbbbbbcaaaaaaaabbbbbbcaaaaaaaabbbbbbc a
 aabaab
 aabaab
 abbabb
 aaazaaaz aaabbcaaabbcaaabbc
 abbabb
 aazaaz azzazz
 accacc


import java.util.*;
import java.lang.*;
import java.io.*;

public class feb20 {

//	            ***                          ++                      
//             +=-==+                      +++=-                     
//            +-:---==+                   *+=----=                   
//           +-:------==+               ++=------==                  
//           =-----------=++=========================                
//          +--:::::---:-----============-=======+++====             
//          +---:..:----::-===============-======+++++++++           
//          =---:...---:-===================---===++++++++++         
//          +----:...:-=======================--==+++++++++++        
//          +-:------====================++===---==++++===+++++      
//         +=-----======================+++++==---==+==-::=++**+     
//        +=-----================---=======++=========::.:-+*****    
//       +==::-====================--:  --:-====++=+===:..-=+*****   
//       +=---=====================-...  :=..:-=+++++++++===++*****  
//       +=---=====+=++++++++++++++++=-:::::-====+++++++++++++*****+ 
//      +=======++++++++++++=+++++++============++++++=======+****** 
//      +=====+++++++++++++++++++++++++==++++==++++++=:...  . .+**** 
//     ++====++++++++++++++++++++++++++++++++++++++++-.     ..-+**** 
//     +======++++++++++++++++++++++++++++++++===+====:.    ..:=++++ 
//     +===--=====+++++++++++++++++++++++++++=========-::....::-=++* 
//     ====--==========+++++++==+++===++++===========--:::....:=++*  
//     ====---===++++=====++++++==+++=======-::--===-:.  ....:-+++   
//     ==--=--====++++++++==+++++++++++======--::::...::::::-=+++    
//     ===----===++++++++++++++++++++============--=-==----==+++     
//     =--------====++++++++++++++++=====================+++++++     
//     =---------=======++++++++====+++=================++++++++     
//     -----------========+++++++++++++++=================+++++++    
//     =----------==========++++++++++=====================++++++++  
//     =====------==============+++++++===================+++==+++++ 
//     =======------==========================================++++++

	// created by : Nitesh Gupta

	public static void main(String[] args) throws Exception {
		first();
//			sec();
	}

	private static void first() throws Exception {
		BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
		StringBuilder sb = new StringBuilder();
		String[] scn = (br.readLine()).trim().split(" ");
		int k = Integer.parseInt(scn[0]);
		
		char[] str = (br.readLine()).toCharArray();
		int n = str.length;
		int[] arr = new int[256];
		for (int i = 0; i < n; i++) {
			arr[str[i]] += 1;
		}
		boolean pos = true;
		for (int i = 0; i < 256; i++) {
			if (arr[i] % k != 0) {
				pos = false;
			}
		}
		if (!pos) {
			sb.append("-1");
		} else {
			StringBuilder ab = new StringBuilder();
			for (int i = 0; i < 256; i++) {
				if (arr[i] > 0) {
					int f = arr[i] / k;
					while (f-- > 0) {
						ab.append((char) (i));
					}
				}
			}
			for (int i = 0; i < k; i++) {
				sb.append(ab);
			}
		}
		System.out.println(sb);
		return;

	}

	private static void sec() throws Exception {
		BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
		int t = Integer.parseInt(br.readLine());
		StringBuilder sb = new StringBuilder();
		while (t-- > 0) {
			String[] scn = (br.readLine()).trim().split(" ");
			int n = Integer.parseInt(scn[0]);
			long[] arr = new long[n];
			scn = (br.readLine()).trim().split(" ");
			for (int i = 0; i < n; i++) {
				arr[i] = Long.parseLong(scn[i]);
			}
			sb.append("\n");
		}
		System.out.println(sb);
		return;

	}

	private static void third() throws Exception {
		BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
		StringBuilder sb = new StringBuilder();
		String[] scn = (br.readLine()).trim().split(" ");
		int n = Integer.parseInt(scn[0]);
		long[] arr = new long[n];
		scn = (br.readLine()).trim().split(" ");
		for (int i = 0; i < n; i++) {
			arr[i] = Long.parseLong(scn[i]);
		}
		System.out.println(sb);
		return;

	}

	public static void sort(long[] arr) {
		int n = arr.length;
		for (int i = 0; i < n; i++) {
			int idx = (int) Math.random() * n;
			long temp = arr[i];
			arr[i] = arr[idx];
			arr[idx] = temp;
		}
		Arrays.sort(arr);
	}

	public static void sort(int[] arr) {
		int n = arr.length;
		for (int i = 0; i < n; i++) {
			int idx = (int) Math.random() * n;
			int temp = arr[i];
			arr[i] = arr[idx];
			arr[idx] = temp;
		}
		Arrays.sort(arr);
	}

	public static void print(long[][] dp) {
		for (long[] a : dp) {
			for (long ele : a) {
				System.out.print(ele + " ");
			}
			System.out.println();
		}
	}

	public static void print(int[][] dp) {
		for (int[] a : dp) {
			for (int ele : a) {
				System.out.print(ele + " ");
			}
			System.out.println();
		}
	}

	public static void print(int[] dp) {
		for (int ele : dp) {
			System.out.print(ele + " ");
		}
		System.out.println();
	}

	public static void print(long[] dp) {
		for (long ele : dp) {
			System.out.print(ele + " ");
		}
		System.out.println();
	}

}