#include <bits/stdc++.h>
using namespace std;
bool sortbysec(const pair<int, int> &a, const pair<int, int> &b) {
  if (a.first == b.first) return (a.second > b.second);
  return (a.first < b.first);
}
bool vis[505];
bool sortbysec2(const pair<int, int> &a, const pair<int, int> &b) {
  return (a.second > b.second);
}
vector<int> v[505];
int main() {
  int n;
  cin >> n;
  pair<int, int> a[n];
  for (int i = 0; i < n; i++) {
    int x;
    cin >> x;
    a[i] = make_pair(i + 1, x);
  }
  sort(a, a + n, sortbysec2);
  int big = a[0].first;
  bool first = 1;
  int coun = 0;
  int maxx = 0;
  int last = 0;
  int last_arry = a[n - 1].second;
  if (a[0].second > 1)
    for (int i = 0; i < n - 1; i++) {
      if (a[i + 1].second <= 1) break;
      maxx++;
      v[a[i].first].push_back(a[i + 1].first);
      a[i].second--;
      a[i + 1].second--;
      coun++;
      last = i + 1;
      for (int j = n - 2; j > last; j--) {
        if (a[j].second != 1) {
          continue;
        }
        if (a[i].second == 0) {
          j = -1;
          continue;
        }
        if (a[j].second == 1) {
          a[i].second--;
          a[j].second--;
          v[a[i].first].push_back(a[j].first);
          coun++;
        }
      }
    }
  if (last_arry == 1) {
    if (a[last].second >= 1) {
      v[a[last].first].push_back(a[n - 1].first);
      coun++;
      a[last].second--;
      a[n - 1].second--;
      maxx++;
    } else {
      for (int i = 0; i < last; i++) {
        if (a[i].second >= 1) {
          v[a[i].first].push_back(a[n - 1].first);
          coun++;
          a[n - 1].second--;
          a[i].second--;
          break;
        }
      }
    }
  }
  for (int i = last + 1; i < n; i++) {
    if (a[last].second == 0) break;
    if (a[i].second != 1) continue;
    v[a[last].first].push_back(a[i].first);
    coun++;
    a[last].second--;
    a[i].second--;
  }
  if (v[a[0].first].size() > 1) maxx++;
  if (coun != n - 1)
    cout << "NO";
  else {
    cout << "YES"
         << " " << maxx << endl
         << coun << endl;
    bool k = 0;
    for (int i = 0; i < 505; i++) {
      for (int j = 0; j < v[i].size(); j++) {
        cout << i << " " << v[i][j];
        if (coun > 1) cout << endl;
        k = 1;
        coun--;
      }
    }
  }
  return 0;
}
