class Program
    {
        static void Main(string[] args)
        {
            string[] num = Console.ReadLine().Split(' ');
            int max = 0;
            int min = int.Parse(num[0]);
            int price = int.Parse(num[2]) % 1000;
            if (int.Parse(num[1]) - min > 1000){
                max = min + 999;
            }
            else
            {
                max = int.Parse(num[1]);
            }
            int change = 1000;
            for (int i = max; i >= min ; i--)
            {
                int a = 1000 + (i * price % 1000);
                if (a == 1000)
                {
                    change = 0;
                }
                if (change > a)
                {
                    change = a;
                }else 
                if (change == 0)
                {
                    break;
                }
            }
            Console.WriteLine(change);
        }
    }