While Mike was walking in the subway, all the stuff in his back-bag dropped on the ground. There were several fax messages among them. He concatenated these strings in some order and now he has string *s*.

He is not sure if this is his own back-bag or someone else's. He remembered that there were exactly *k* messages in his own bag, each was a palindrome string and all those strings had the same length.

He asked you to help him and tell him if he has worn his own back-bag. Check if the given string *s* is a concatenation of *k* palindromes of the same length.
The first line of input contains string *s* containing lowercase English letters (1 ≤ |*s*| ≤ 1000).

The second line contains integer *k* (1 ≤ *k* ≤ 1000).
n, t = map(int, input().split(" "))
x = 1
while(n != 0) :
    x = x*1
    n = n-1
k = x//10
flag = 0 
for i in range(k, x) :
    if(i%t == 0) :
        flag = 1
        print(i)
        break
    else :
        flag = 0
if(flag == 0) :
    print(-1) 