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 PyPy3 (2.4.0) (judge verdict: Accepted)

# -*- coding: utf-8 -*-
# B

import sys
from collections import defaultdict, deque
from heapq import heappush, heappop
import math
import bisect

# 再起回数上限変更
# sys.setrecursionlimit(1000000)

N = int(input())
S = input()
num = len(S)
if num % 2 == 1:
    print('No')
    sys.exit()

num = num //2
if S == S[:num]*2:
    print('Yes')
else:
    print('No')