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())
b = a//1000

print(b*1000 - a)

a = int(input())
if a == 1000:
    b = 1
elif a %1000 == 0:
    b = a//1000
else:
    b = a//1000 + 1
print(b*1000 - a)