Problem:
Score : 200 points

Problem Statement

Given are a positive integer N and a string S of length N consisting of lowercase English letters.

Determine whether the string is a concatenation of two copies of some string.
That is, determine whether there is a string T such that S = T + T.

Constraints

1 \leq N \leq 100

S consists of lowercase English letters.

|S| = N

Input

Input is given from Standard Input in the following format:

N
S

Output

If S is a concatenation of two copies of some string, print Yes; otherwise, print No.

Sample Input 1

6
abcabc

Sample Output 1

Yes

Let T = abc, and S = T + T.

Sample Input 2

6
abcadc

Sample Output 2

No

Sample Input 3

1
z

Sample Output 3

No

Solution in C (GCC 5.4.1) (judge verdict: Runtime Error)

#include <stdio.h>
#include <string.h>


int main(){
	int n;
	if (scanf("%d", &n) != 1){printf("No\n"); return -2;}
	char s[n+1];
	if (scanf("%s", s) != 1){printf("No\n"); return -2;}
	if(strlen(s) != n){printf("No\n"); return -2;}
	
	if(n%2 != 0){printf("No\n"); return -1;}
	for(int i = 0; i < n/2; i++){
		if(s[i] != s[i+n/2]){printf("No\n"); return -1;}		
	}
	printf("Yes\n");
	return 0;

}