using System;
using System.Collections.Generic;
using System.Linq;

class Program
{
    static void Main(string[] args)
    {
        var input = Console.ReadLine().Split().Select(long.Parse).ToArray();
        var L = input[0];
        var R = input[1];
        var C = input[2];
        var min = 999L;

        for (long i = L; i <= R; i++)
        {
            var charge = 1000 - (C * i) % 1000;
            if (charge == 1000)
            {
                min = 0;
                break;
            }
            min = Math.Min(min, charge);
        }
        Console.WriteLine(min);
    }
}