#include<bits/stdc++.h>
using namespace std;
int main(){
	int a,b,c,d;
	cin>>a>>b>>c>>d;
	int max=a;
	if (max<b){
		max=b;
	}
	if (max<c){
		max=c;
	}
	if (max<d){
		max=d;
	}
	printf("%d",max);
	return 0;
}
/**************************************************************
	Problem: 1305
	User: xiaojingxuan
	Language: C++
	Result: Accepted
	Time:20 ms
	Memory:2072 kb
****************************************************************/