import java.util.Scanner;
public class Main {
public static void main(String[] args) {
Scanner scanner = new Scanner(System.in);
int[] arr = new int[4];
for(int i = 0; i < arr.length; i++) {
arr[i] = scanner.nextInt();
}
int max = arr[0];
for(int i = 1; i < arr.length; i++) {
if(max < arr[i]) {
max = arr[i];
}
}
System.out.println(max);
}
}