#include <bits/stdc++.h>
using namespace std;
const long long N = 1e5 + 2;
const long long mod = 1000000007;
int main() {
  ios_base::sync_with_stdio(0);
  cin.tie(NULL);
  long long n;
  cin >> n;
  vector<long long> a(n + 1);
  vector<pair<long long, long long>> b;
  vector<long long> c;
  for (int i = 1; i <= n; i++) {
    cin >> a[i];
    if (a[i] > 1)
      b.push_back({a[i], i});
    else
      c.push_back(i);
  }
  if (b.size() == 0) {
    cout << "NO";
    return 0;
  }
  vector<pair<long long, long long>> ans;
  for (int i = 1; i < b.size(); i++) {
    ans.push_back({b[i - 1].second, b[i].second});
    b[i - 1].first--;
    b[i].first--;
  }
  long long len = b.size() - 1;
  len += min(2, (int)c.size());
  if (c.size()) {
    ans.push_back({b[0].second, c.back()});
    c.pop_back();
    b[0].first--;
  }
  if (c.size()) {
    ans.push_back({b.back().second, c.back()});
    c.pop_back();
    b.back().first--;
  }
  for (int i = 0; i < c.size(); i++) {
    long long ok = 0;
    for (int j = 0; j < b.size(); j++) {
      if (b[j].first) {
        b[j].first--;
        ans.push_back({b[j].second, c[i]});
        ok = 1;
        break;
      }
    }
    if (!ok) {
      cout << "NO";
      return 0;
    }
  }
  cout << "YES " << len << "\n";
  cout << ans.size() << "\n";
  for (auto e : ans) cout << e.first << " " << e.second << "\n";
}
