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.
a = int(input())

print(a%1000)
a = int(input())

if a%1000 == 0:
    print(0)
else:
    print(1000-a%1000)