import sys
read = sys.stdin.buffer.read
readline = sys.stdin.buffer.readline
readlines = sys.stdin.buffer.readlines
sys.setrecursionlimit(10 ** 7)

a, b = map(int, read().split())
n = 0
for i in range(10000):
    n = a * n + b
    if n == 0:
        print(i + 1)
        exit()
print(-1)