#include <bits/stdc++.h>
using namespace std;

//repetition
#define FOR(i,a,b) for(ll i=(a);i<(b);++i)
#define rep(i, n) for(ll i = 0; i < (ll)(n); i++)

//container util
#define all(x) (x).begin(),(x).end()

//typedef
typedef long long ll;
typedef vector<int> VI;
typedef vector<VI> VVI;
typedef vector<ll> VLL;
typedef vector<VLL> VVLL;
typedef vector<string> VS;
typedef pair<int, int> PII;
typedef pair<ll, ll> PLL;

//const value
//const ll MOD = 1e9 + 7;
//const int dx[] = {0,1,0,-1};//{0,0,1,1,1,-1,-1,-1};
//const int dy[] = {1,0,-1,0};//{1,-1,0,1,-1,0,1,-1};

//conversion
inline int toInt(string s) {int v; istringstream sin(s);sin>>v;return v;}
inline ll toLL(string s) {ll v; istringstream sin(s);sin>>v;return v;}
template<class T> inline string toString(T x) {ostringstream sout;sout<<x;return sout.str();}


int main(){
  ios::sync_with_stdio(false);
  cin.tie(0);
  ll n;
  cin >> n;
  cin.ignore();
  VLL a(n);
  string s;
  rep(i,3){
    if(getline(cin,s)){
      a[i] = toLL(s);
      //cerr << a[i] << endl;
    }else{
      cout << "\"assert\"" <<  endl;
      return 0;
    }
  }

  VLL v;
  rep(i,3){
    FOR(j,i+1,3){
      v.push_back(a[i] + a[j]);
    }
  }
  sort(all(v));
  v.erase(unique(v.begin(),v.end()),v.end());
  reverse(all(v));
  if(v.size() >= 2){cout  << v[1] << endl;}
  else cout << "\"assert\"" <<  endl;

  return 0;
}