#include <cmath>
#include <cstdio>
#include <vector>
#include <iostream>
#include <algorithm>
using namespace std;


int max_value(int a, int b, int c, int d) {
    
    int inputs[] = {a, b, c, d};
    int max_v = inputs[0];
    int size = sizeof(inputs) / sizeof(inputs[0]);
    
    for (int i=0; i < size; i++) {
        if (inputs[i] > max_v) {
            max_v = inputs[i];
        };
    };
    
    return max_v;
}
int main() {
    /* Enter your code here. Read input from STDIN. Print output to STDOUT */   
    int a;
    int b;
    int c;
    int d;
    scanf("%d\n", &a);
    scanf("%d\n", &b);
    scanf("%d\n", &c);
    scanf("%d\n", &d);
    
    printf("%d\n", max_value(a,  b,  c, d));
    return 0;
}