/*
 * 
 * 	^v^
 * 
 */
#include <iostream>
#include <numeric>
#include <set>
#include <iomanip>
#include <chrono>
#include <queue>
#include <string>
#include <vector>
#include <functional>
#include <map>
#include <bitset>
#include <algorithm>
#include <array>
#include <random>

using namespace std;

using ll = long long int;
using ld = long double;

#define iamtefu ios_base::sync_with_stdio(false); cin.tie(0);
#define fl(i,a,n) for (ll i{a}; i<n; i++)
#define fr(x,s) for(auto x:s)
#define rfl(i,a,n) for (ll i{n-1}; i>=a; i--)
#define ty int _; for(cin>>_; _--;)
#define print(a) for(auto ele:a){cout<<ele<<" ";}cout<<'\n';
#define all(x) x.begin(), x.end()

template <typename L, typename R>
inline bool chmax(L &a, R b){if (a<b){a=b;return 1;}return 0;}
template <typename L, typename R>
inline bool chmin(L &a, R b){if (a>b){a=b;return 1;}return 0;}

template <typename L, typename R>
ostream& operator<<(ostream &fout, const pair<L, R> &p){
  fout<<"{"<<p.first<<","<<p.second<<"}";
  return fout;
}

template <typename L, typename R, typename U>
ostream& operator<<(ostream &fout, const tuple<L, R, U> &p){
  auto &[l, r, u] = p;
  fout<<"{"<<l<<","<<r<<","<<u<<"}";
  return fout;
}

template <typename L, typename R, typename U, typename T>
ostream& operator<<(ostream &fout, const tuple<L, R, U, T> &p){
  auto &[l, r, u, t] = p;
  fout<<"{"<<l<<","<<r<<","<<u<<","<<t<<"}";
  return fout;
}

template <typename L, typename R, typename U, typename T, typename V>
ostream& operator<<(ostream &fout, const tuple<L, R, U, T, V> &p){
  auto &[l, r, u, t, v] = p;
  fout<<"{"<<l<<","<<r<<","<<u<<","<<t<<","<<v<<"}";
  return fout;
}

template <typename T>
ostream& operator<<(ostream &fout, const vector <T> &v){
  for (auto &x:v){
    fout<<x<<" ";
  }
  fout<<"\n";
  return fout;
}

template <typename T>
ostream& operator<<(ostream &fout, const set <T> &st){
  for (auto &x:st){
    fout<<x<<" ";
  }
  fout<<"\n";
  return fout;
}

template <typename T>
ostream& operator<<(ostream &fout, const multiset <T> &st){
  for (auto &x:st){
    fout<<x<<" ";
  }
  fout<<"\n";
  return fout;
}

template <typename K, typename V>
ostream& operator<<(ostream &fout, const map<K, V> &mp){
  fout<<"[";
  for (auto &[x,y]:mp){
    fout<<x<<":"<<y<<" ";
  }
  fout<<"]\n";
  return fout;
}

ll gcd(ll a, ll b){
  if (b==0){
    return a;
  }
  return gcd(b, a%b);
}

mt19937 rng(chrono::high_resolution_clock::now().time_since_epoch().count());

ll pw(ll a, ll b, ll m){
  ll res=1;
  a%=m;
  while (b){
    if (b&1){
      res=(res*a)%m;
    }
    a=(a*a)%m;
    b/=2;
  }
  return res;
}

void scn(){
  // not necessarily distinct
  // right down

  ll a, b, o, ab; cin>>a>>b>>o>>ab;
  cout<<max({a+ab, b+ab, ab+o+max(a, b), ab})<<'\n';
}

int main(){
  iamtefu;
#if defined(airths)
  auto t1=chrono::high_resolution_clock::now();
  freopen("input.txt", "r", stdin);
  freopen("output.txt", "w", stdout);
#endif
  //ty
  {
    scn();
  }
#if defined(airths)
  auto t2=chrono::high_resolution_clock::now();
  ld ti=chrono::duration_cast<chrono::nanoseconds>(t2-t1).count();
  ti*=1e-6;
  cerr<<"Time: "<<setprecision(12)<<ti;
  cerr<<"ms\n";
#endif
  return 0;
}