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 Python (3.4.3) (judge verdict: Wrong Answer)

import sys

N = int(input())
S = list(str(input()))

if(N%2==1 or N==0):
    print("No")
    sys.exit()

if(N==2 and S[0]!=S[1]):
    print("No")
    sys.exit()
else:
    print("Yes")

for x in range(0, N//2-1):
    if(S[x]!=S[N//2+x]):
        print("No")
        sys.exit()

print("Yes")