a, b = map(int, input().split())
if a == 0:
    print(1)
else:
    b = -b
    x = 0
    ans = 0
    s = set()
    while x % a == 0 and x // a + b not in s:
        ans += 1
        x = x // a + b
        s.add(x)
        if x == 0:
            print(ans)
            break
    else:
        print(-1)