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))
