#pragma GCC optimize("O3")
#pragma GCC optimize("Ofast")
#pragma GCC optimize("unroll-loops")
#pragma GCC target("avx,avx2")
#include <bits/stdc++.h>
#define INF 1000000001LL
#define LNF 1000000000000000001LL
#define MOD 998244353LL
#define MAX 2001
#define long long long
#define all(x) x.begin(),x.end()
using namespace std;

int main()
{
	ios_base::sync_with_stdio(0); 
    cin.tie(0);

    int a,b,c,d;
    cin >> a >> b >> c >> d;
    
    cout << max(a+c+d,b+c+d) << endl;
    return 0;
}