#include<stdio.h>
#include<stdlib.h>
#include<time.h>
#include<math.h>
#include<ctype.h>
int max_of_four(int a,int b,int c,int d);
int main()
{   
    int a,b,c,d,res;
    int max_of_four(int a,int b,int c,int d){
        if (a>=b && a>=c && a>=d){
            return a;
        }  
        else if (b>=a && b>=c && b>=d){
            return b;
        }
        else if (c>=a && c>=b && c>=d){
            return c;
        }
        else {
            return d;
        }
    }
    scanf("%d\n%d\n%d\n%d",&a,&b,&c,&d);
    res=max_of_four(a,b,c,d);
    printf("%d",res);
    return 0;
}

#include <stdio.h>
/*
Add `int max_of_four(int a, int b, int c, int d)` here.
*/
int max_of_four(int a ,int b , int c , int d);
int main() {
    int a, b, c, d;
    scanf("%d %d %d %d", &a, &b, &c, &d);
    int ans = max_of_four(a, b, c, d);
    printf("%d", ans);
    
    return 0;
}
int max_of_four(int a ,int b , int c , int d)
{
    // if a is the maximum 
    switch (a > b && a > c && a > d) {
    case 1:
        
        return a;
    case 0:
     // if b is the maximum 
        switch (b > a && b > c && b > d) {
        case 1:
        
            return b;
        case 0:
        // if c is the maximum 
            switch (c > a && c > b && c > d) {
            case 1:
            
                return c;
            case 0:
            // if d is the maximum 
                return d;
            }    
        }
     // in this case all numbers are equls   
    default:
        return a;
        
    }
}

int max_of_four(int a, int b, int c, int d)
{
    int res = 0;
    if (a > res)
        res = a;
    if (b > res)
        res = b;
    if (c > res)
        res = c;
    if(d > res)
        res = d;
    return res;
}