#include <algorithm>
#include <bitset>
#include <cassert>
#include <cctype>
#include <chrono>
#define _USE_MATH_DEFINES
#include <cmath>
#include <cstdio>
#include <cstring>
#include <ctime>
#include <deque>
#include <functional>
#include <iostream>
#include <iterator>
#include <map>
#include <queue>
#include <random>
#include <set>
#include <sstream>
#include <string>
#include <tuple>
#include <utility>
#include <vector>
using namespace std;

#define FOR(i,m,n) for(int i=(m);i<(n);++i)
#define REP(i,n) FOR(i,0,n)
#define ALL(v) (v).begin(),(v).end()

const int INF = 0x3f3f3f3f;
const long long LINF = 0x3f3f3f3f3f3f3f3fLL;
const double EPS = 1e-8;
const int MOD = 1000000007; // 998244353;
const int dy[] = {1, 0, -1, 0}, dx[] = {0, -1, 0, 1};
/*-------------------------------------------------*/
vector<string> split(string str, string target) {
  vector<string> res;
  if (!target.empty()) {
    size_t target_len = target.length();
    for (size_t pos = 0; (pos = str.find(target)) != str.npos;) {
      res.emplace_back(str.substr(0, pos));
      str = str.substr(pos + target_len);
    }
    res.emplace_back(str);
  } else {
    res.emplace_back(str);
  }
  return res;
}

int main() {
  cin.tie(0); ios::sync_with_stdio(false);
  // freopen("input.txt", "r", stdin);

  string s; getline(cin, s);
  int n = stoi(s);
  getline(cin, s);
  vector<string> spl = split(s, " ");
  if (spl.size() == 1) {
    vector<long long> a(3);
    a[0] = stoll(s);
    FOR(i, 1, 3) cin >> a[i];
    set<long long> tmp;
    REP(i, 3) FOR(j, i + 1, 3) tmp.emplace(a[i] + a[j]);
    auto it = tmp.rbegin();
    --it;
    cout << *it << '\n';
  } else {
    cout << "\"assert\"\n";
  }
}