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