import sys

sys.setrecursionlimit(10 ** 8)

input = sys.stdin.readline


def main():
    A, B = [int(x) for x in input().split()]

    N = 0
    ans = 0
    while True:
        ans += 1
        N = A * N + B
        if N == 0:
            print(ans)
            return

        if ans == 10 ** 4:
            break

    print(-1)

    
    

if __name__ == '__main__':
    main()