using static System.Math;
using System;

public class Hello
{
    static void Main()
    {
        string[] line = Console.ReadLine().Trim().Split(' ');
        var L = long.Parse(line[0]);
        var r = long.Parse(line[1]);
        var c = long.Parse(line[2]);
        getAns(L, r, c);
    }
    static void getAns(long L, long r, long c)
    {
        if (c % 1000 == 0) { Console.WriteLine(0); return; }
        c %= 1000;
        r = Min(r, L + 1000);
        var ans = long.MaxValue;
        for (long i = L; i <= r; i++)
        {
            var t = 1000 - (c * i) % 1000;
            if (t == 0 | t == 1000) { Console.WriteLine(0); return; }
            ans = Min(ans, t);
        }
        Console.WriteLine(ans);
    }
}