#include<bits/stdc++.h>
using namespace std;
int main(){
	// input
	int a,b,o,w;
	cin >> a >> b >> o >> w;
	// validate
	const int mn = 0, mx = 1000;
	assert(mn <= a && a <= mx);
	assert(mn <= b && b <= mx);
	assert(mn <= o && o <= mx);
	assert(mn <= w && w <= mx);
	assert(a+b+o+w > mn);
	// solve + output
	// int ans = max(o+a+w,o+b+w); // correct answer
	int ans = max({o+a,o+b,a+w,b+w});
	cout << ans << endl;
}