A, B = map(int, input().split())
N = B
if B==0:
  print(1)
for n in range(1,10**5):
  if B == 0:
    break
  if A*N+B == 0:
    print(n+1)
    break
  elif abs(N) > abs(A*N+B):
    N = A*N+B
  else:
    print(-1)
    break