#include <bits/stdc++.h>
using namespace std;
bool isprime(long long n) {
  if (n == 1) return false;
  for (long long i = 2; i * i <= n; i++) {
    if (n % i == 0) return false;
  }
  return true;
}
long long gcd(long long a, long long b) {
  if (b == 0) {
    return a;
  }
  return gcd(b, a % b);
}
long long lcm(long long a, long long b) { return (a * b) / gcd(a, b); }
long long power(long long x, long long y) {
  long long res = 1;
  if (x == 0) return 0;
  while (y > 0) {
    if (y & 1) {
      res *= x;
    }
    y = y >> 1;
    x = (x * x);
  }
  return res;
}
long long modInverse(long long n, long long p) { return power(n, p - 2); }
signed main() {
  ios_base::sync_with_stdio(false);
  cin.tie(0);
  cout.tie(0);
  long long i, j, k, zx, t;
  zx = 1;
  while (zx--) {
    long long n, m;
    cin >> n;
    vector<pair<long long, long long>> a;
    long long has = 0;
    vector<long long> one;
    map<long long, long long> c;
    for (i = 0; i < n; i++) {
      long long u;
      cin >> u;
      if (u == 1) {
        one.push_back(i + 1);
        c[i] = 1;
      } else {
        a.push_back({u, i + 1});
      }
    }
    if (a.size() == 0) {
      if (one.size() > 2) {
        cout << "NO" << endl;
      } else {
        cout << "YES 1" << endl;
        cout << "1" << endl;
        cout << "1 2" << endl;
      }
      continue;
    }
    map<long long, long long> ans;
    long long d = 0;
    for (i = 1; i < a.size(); i++) {
      ans[a[i - 1].second] = a[i].second;
      a[i - 1].first--;
      a[i].first--;
      d++;
    }
    i = 0;
    if (one.size() > i) {
      ans[one[i]] = a[0].second;
      d++;
      i++;
      a[0].first--;
    }
    if (one.size() > i) {
      if (a[0].first != 0 || a.size() > 1) {
        ans[one[i]] = a[a.size() - 1].second;
        a[a.size() - 1].first--;
        i++;
        d++;
      }
    }
    vector<long long> rem;
    for (k = 0; k < a.size(); k++) {
      for (j = 0; j < a[k].first; j++) {
        rem.push_back(a[k].second);
      }
    }
    j = 0;
    while (i < one.size() && j < rem.size()) {
      ans[one[i]] = rem[j];
      i++;
      j++;
    }
    if (i < one.size()) {
      cout << "NO" << endl;
    } else {
      cout << "YES " << d << endl;
      cout << ans.size() << endl;
      for (auto &i : ans) {
        cout << i.first << " " << i.second << endl;
      }
    }
  }
}
