Problem:
Score : 300 points

Problem Statement

Given any integer x, Aoki can do the operation below.

Operation: Replace x with the absolute difference of x and K.

You are given the initial value of an integer N. Find the minimum possible value taken by N after Aoki does the operation zero or more times.

Constraints

0 ≤ N ≤ 10^{18}

1 ≤ K ≤ 10^{18}

All values in input are integers.

Input

Input is given from Standard Input in the following format:

N K

Output

Print the minimum possible value taken by N after Aoki does the operation zero or more times.

Sample Input 1

7 4

Sample Output 1

1

Initially, N=7.

After one operation, N becomes |7-4| = 3.

After two operations, N becomes |3-4| = 1, which is the minimum value taken by N.

Sample Input 2

2 6

Sample Output 2

2

N=2 after zero operations is the minimum.

Sample Input 3

1000000000000000000 1

Sample Output 3

0

Solution in Pascal (FPC 3.0.4) (judge verdict: Wrong Answer)

program ReplacingInteger;
var
    x, y, z : int64;
begin
    readln(x, y);
    if (x > y) then begin
        if (x mod y = 0) then 
            writeln(0)
            else begin
                z := x div y;
                if (z <  abs(z - y)) then 
                    writeln(z)
                    else
                        writeln(abs(z - y));
            end;
    end
    else begin
        if (x < y) then
            writeln(abs(x))
            else if (x = y) then
                writeln(0);
        end;
end.