#include<bits/stdc++.h>
using namespace std;
int main(){
	int a,b,c,d,maxx;
	cin>>a>>b>>c>>d;
	maxx=a;
	if(b>maxx){
		maxx=b;
	}
	if(c>maxx){
		maxx=c;
	}
	if(d>maxx){
		maxx=d;
	}
    printf("%d",maxx);
	return 0;
}

/**************************************************************
	Problem: 1305
	User: chenzelin
	Language: C++
	Result: Accepted
	Time:23 ms
	Memory:2072 kb
****************************************************************/