#include <bits/stdc++.h>
#include <atcoder/all>
using namespace std;
using namespace atcoder;
using ll = long long;
using ld = long double;

int main() {
  int N; cin >> N;
  string dummy; getline(cin, dummy);
  ll a[3];
  int i = 0;
  string num;
  while (i < 3) {
    getline(cin, num);
    if (num.find(' ') != -1) {
      cout << "\"assert\"" << endl;
      return 0;
    } 
    a[i] = stoll(num);
    i++;
  }
  set<ll> ans;
  for (int i = 0; i < 3; i++) {
    for (int j = i + 1; j < 3; j++) {
      ans.insert(a[i] + a[j]);
    }
  }
  cout << *prev(prev(ans.end())) << endl;
  return 0;
}