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(void){
    int num;
    scanf("%d",&num);
    char moji[num];
    char copy[num];

    scanf("%s",moji);

    for(int i = 0; i < num/2; i++){
        copy[i] = moji[i];
    }
    
    //printf("%s\n",moji);
    //printf("%s\n",copy);

    strcat(copy,copy);//strcat(引数1,引数2) 引数1に引数2を加える(文字列)
    //printf("%s\n",copy);
    if(strcmp(copy,moji)==0){   //strcmp 文字列比較
        printf("Yes\n");
    }else{
        printf("No");
    }
    return 0;
}