#include<iostream>
using namespace std;

int main(){
	int a,b,c,d,m;
	cin>>a>>b>>c>>d;
	//假设a最大
	m = a;
	//如果b比最大数m大
	if(b > m){
		m = b;
	}
	
	if(c > m){
		m = c;
	} 
	
	if(d > m){
		m = d;
	} 
	
	cout<<m<<endl;
}
/**************************************************************
	Problem: 1305
	User: admin
	Language: C++
	Result: Accepted
	Time:13 ms
	Memory:2072 kb
****************************************************************/