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())
if t < 10:
    print(int(n*str(t)))
elif t == 10:
    if n == 1:
        print(-1)
    else:
        print((n-1)*str(1) + '0')