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())
ans = N
while ans > 999:
  ans -= 1000
print(ans)
N = int(input())
ans = N
while ans > 999:
  ans -= 1000
if ans == 0:
  print(ans)
else:
  print(1000-ans)