A, B = map(int, input().split())
count = 0
N = 0
if ((A == -1 or A == 1) and (A * B < 0 or B < 0)) or B == 0:
    while 1:
        count += 1
        N = A * N + B
        if N == 0:
            break
    print(count)
else:
    print(-1)