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> 

int comp(char a , char b); 
int main(){
	unsigned int i;
        unsigned int j;	
	unsigned int N; 
	char S[N+1]; 
	scanf("%d",&N); 
	scanf("%s",&S);
	if (N%2!=0){
		printf("No"); 
		return 0;
	}
	for(i = 0; i < N/2; i++){
		if(comp(S[i], S[i+(N/2)])){
			printf("No");
			return 0; 
		}
	}
	printf("Yes");
}	


int comp(char a , char b){
	if (a == b){
		return 0;
	}	
	else{
		return 1; 
	}
}