from sys import stdin


def main():
    input = lambda: stdin.readline()[:-1]
    A, B = map(int, input().split())

    if A > 0 and B > 0:
        print(-1)
        return

    ans, n = 0, 0
    while 1:
        n = A * n + B
        if not n:
            break
        ans += 1
    print(ans)


main()