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 JavaScript (node.js v5.12) (judge verdict: Runtime Error)

function main(input){
    var tmp = input.split('\n');
    var n = perseInt(tmp[0]);
    var s = tmp[1];
    if(n%2==0){
        var t = s.slice(0,n/2-1);
        if(t[0]==t[1]){
            console.log("Yes");
        }else{
            console.log("No");
        }
    }else{
        console.log("No");
    }
}
main(require("fs").readFileSync("/dev/stdin", "utf8"));