import java.io.*;
import java.util.*;

public class Solution {
	private static int max(int a, int b) {
        return a > b ? a : b;
    }

    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        PrintWriter out = new PrintWriter(System.out);
        int a = in.nextInt();
        int b = in.nextInt();
        int c = in.nextInt();
        int d = in.nextInt();
        out.println(max(max(max(a, b), c), d));
        out.flush();
    }
}