#define loop(i,from,to) for (int i = from; i < to; ++i)
#define qAll(q) q.begin(), q.end()
#define X first
#define Y second
#include <bits/stdc++.h>

using std::cin;
using std::cout;
using std::endl;
using std::vector;
using std::string;
using std::pair;
using std::set;

const int INF = 1e9+7;
const double eps = 1e-6;
template <typename T> void reverse(T &a) {
  long long s = a.size();
  for (long long i = 0; i < s / 2; ++i)
    std::swap(a[i], a[s - i - 1]);
}

long long S(int a, int b, int c) {
  long long p = a + b + c;
  return 1LL * p * (p - 2 * a) * (p - 2 * b) * (p - 2 * c);
}

bool check(int a, int b, int c) {
  return a + b > c && a + c > b && b + c > a;
}

signed main() {
  std::ios::sync_with_stdio(false);
  cin.tie(0);
  cout.tie();
  int n, T; cin >> n;
  vector<int> data;
  loop(i, 0, n) {
    cin >> T;
    data.emplace_back(T);
  }
  if (n < 3) cout << -1;
  else {
    vector< pair<int, int> > sides;
    loop(i, 0, n) sides.push_back({data[i], i + 1});
    std::sort(sides.rbegin(), sides.rend());
    bool f = false;
    long long mx = -INF;
    loop(i, 0, n - 2) {
      int j = i + 1, k = i + 2;
      if (check(sides[i].first, sides[j].first, sides[k].first)) {
        assert(mx <= S(sides[i].first, sides[j].first, sides[k].first));
        if (mx <= 0)
        {
          mx = S(sides[i].first, sides[j].first, sides[k].first);
          cout << std::fixed << std::setprecision(6) <<
            sqrt((long double) mx) / 4 << endl;
          cout << sides[i].second << " " << sides[j].second << " " << sides[k].second;
          f = true;
        }
      }
    }
    if (!f) cout << -1;
  }
  //std::cout << "Hello World!\n";
  return 0;
}