N, D = map(int, input().split())
import sys
if N == D:
  print(0)
  sys.exit()

xs = [1 for n in range(N)]

#print(xs)
for index, jump in enumerate(range(0, 1000, D)):
  point = jump%N
  if xs[point] is None:
    print(index-1)
    #print(xs)
    break
  xs[point] = None