#include <bits/stdc++.h>
using namespace std;
int main(){
    float a,b,c,d,max;
    cin>>a>>b>>c>>d;
    max=a;
    if (a>max) max=a;
    if (b>max) max=b; 
	if (c>max) max=c;
	if (d>max) max=d;
	cout<<max;
}
/**************************************************************
	Problem: 1305
	User: wngjinming
	Language: C++
	Result: Accepted
	Time:12 ms
	Memory:2072 kb
****************************************************************/