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: Runtime Error)

def judge1(Num,a):
    s = list(range(Num))
    for l in range(2,Num):
        if Num%l == 0:
            alpha = list(a)
            j = int(Num/l - 1)
            b = []
            c = []
            for i in range(j+1):
                b.append(alpha[i])
            for k in range(l):
                c = c + b
            if alpha == c:
                s[l] = 1
            else:
                s[l] = 0
        else:
            s[l] = 0
    return s

N = int(input())
S = input()
a = judge1(N,S)
if 1 == a[2]:
    print("yes")
else:
    print("No")