#include <bits/stdc++.h>

using namespace std;

#define REP(i,n) for(int i=0; i<(int)(n); i++)

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

  int n;
  cin >> n;

  vector<long long> v(3);

  string s;
  getline(cin, s);  // newline
  getline(cin, s);

  if (count(s.begin(), s.end(), ' ') > 1)
    cout << "assert" << endl;
  else {
    v[0] = stoll(s);
    cin >> v[1] >> v[2];

    vector<long long> sum;
    REP (i, 3) REP (j, i) sum.push_back(v[i] + v[j]);
    sort(sum.rbegin(), sum.rend());
    sum.erase(unique(sum.begin(), sum.end()), sum.end());
    cout << sum[1] << endl;
  }
    
  return 0;
}