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

/**************************************************************
	Problem: 1305
	User: zhangziang
	Language: C++
	Result: Accepted
	Time:12 ms
	Memory:2072 kb
****************************************************************/