#include<bits/stdc++.h>
using namespace std;
int main(){
    int a,b,c,d;
    cin>>a>>b>>c>>d;
    int max=a;
    if (max<b){
        max=b;
    }
    if (max<c){
        max=c;
    }
    if (max<d){
        max=d;
    }
    printf("%d",max);
    return 0;
}
/**************************************************************
	Problem: 1305
	User: HUANGYIBO
	Language: C++
	Result: Accepted
	Time:14 ms
	Memory:2072 kb
****************************************************************/