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())
print(n % 1000)
n = int(input())
if n % 1000 == 0:
  print(0)
else:
  print(1000-(n%1000))
  