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: Wrong Answer)

"use strict";
const Main = (input) =>{
   let xs = input.trim().split('\n');
   let xs1= xs[1].trim().split('').sort();
   //console.log(xs1);
   let count = 0;
   for(let i =0; i<xs[0]; i++){
     for(let j =i+1; j<xs[0]; j++){
         if(xs1[i]==xs1[j]){
         count +=1;
         }else{
         count +=0;
         }
     } 
   }
   //console.log(count);
   if(count >= xs[0]/2){
     console.log('Yes');
   }else{
     console.log('No');
   }
}
Main(require('fs').readFileSync('/dev/stdin','utf8'));