Problem:
Score : 100 points

Problem Statement

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.

Constraints

1 \leq N \leq 10000

N is an integer.

Input

Input is given from Standard Input in the following format:

N

Output

Print the amount of change as an integer.

Sample Input 1

1900

Sample Output 1

100

We will use two 1000-yen bills to pay the price and receive 100 yen in change.

Sample Input 2

3000

Sample Output 2

0

We can pay the exact price.

Solution in Pascal (FPC 3.0.4) (judge verdict: Accepted)

var
	n:Smallint;
begin
    read(n);
    if n=0 then begin
        write(0)
    end
    else if n<=1000 then begin
        write(1000-n)
    end
    else if n<=2000 then begin
        write(2000-n)
    end
    else if n<=3000 then begin
        write(3000-n)
    end
    else if n<=4000 then begin
        write(4000-n)
    end
    else if n<=5000 then begin
        write(5000-n)
    end
    else if n<=6000 then begin
        write(6000-n)
    end
    else if n<=7000 then begin
        write(7000-n)
    end
    else if n<=8000 then begin
        write(8000-n)
    end
    else if n<=9000 then begin
        write(9000-n)
    end
    else begin
        write(10000-n)
    end;
end.