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
a=int(input())
b=list(input())
c=0
if a==1:
  print('No')
  sys.exit()
for i in range(a//2):
  if  b[i]==b[i+(a//2)]:
    c+=1
  else:
    pass
if c==a//2:
  print('Yes')
else:
  print('No')