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())
k=n%1000+1
print(k*1000-n)
n = int(input())
k = (n//1000) + 1
if n%1000 == 0:
  print(0)
else :
  print(1000*k-n)