while 1 == 1:
 fs = 1
 fn = 1
 fm = 1
 a, b = list(map(int, input().split()))
 if a == b:
  if a == 0:
   break
 else:
  for i in range(1, a + 1):
   fn = fn * i
  for i in range(1, (a - b) + 1):
   fs = fs * i
  for i in range(1, b + 1):
   fm = fm * i
  ans = fn / (fs * fm)
  print(a + " things taken " + b + " at a time is " + ans + " exactly.")