#include<bits/stdc++.h>
using namespace std;
int main(){
	int a,b,c,d,max;
	cin>>a>>b>>c>>d;
	max=a;
	if(b>max) max=b;
	if(c>max) max=c;
	if(d>max) max=d;
	cout<<max;
}

    
  
/**************************************************************
	Problem: 1305
	User: fandaohan
	Language: C++
	Result: Accepted
	Time:46 ms
	Memory:2072 kb
****************************************************************/