# coding: utf-8
# Your code here!
import sys
read = sys.stdin.read
readline = sys.stdin.readline 
readlines = sys.stdin.readlines

#n = int(input())
#ab = [[int(i) for i in readline().split()] for _ in range(n)]
a,b = [int(i) for i in read().split()]


x = b
for i in range(100000):
    if x == 0:
        print(1+i)
        break
    x = a*x+b
else:
    print(-1)