We will buy a product for N yen (the currency of Japan) at a shop.  If we use only 1000-yen bills to pay the price, how much change will we receive?  Assume we use the minimum number of bills required.
N = int(input())
res =N
while res>= 1000 :
  res = res -1000
print(res)
N = int(input())
res =N
while res> 1000 :
  res = res -1000
print(1000-res)
