import java.io.BufferedReader;
import java.io.InputStreamReader;

public class Main {
	public static void main(String[] args) throws Exception {
		BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
		String[] sa = br.readLine().split(" ");
		int l = Integer.parseInt(sa[0]);
		int r = Integer.parseInt(sa[1]);
		int c = Integer.parseInt(sa[2]);
		br.close();

		boolean[] b = new boolean[1000];
		for (int i = l; i <= r; i++) {
			int a = (int) ((long) c * i % 1000);
			if (b[a]) {
				break;
			}
			b[a] = true;
		}

		if (b[0]) {
			System.out.println(0);
			return;
		}
		for (int i = 999; i > 0; i--) {
			if (b[i]) {
				System.out.println(1000 - i);
				return;
			}
		}
	}
}