#include <bits/stdc++.h>
using namespace std;
void fun() {}
long long int md = 998244353;
long long int __gcd(long long int a, long long int b) {
  if (b == 0) return a;
  return __gcd(b, a % b);
}
long long int poww(long long int a, long long int b, long long int md) {
  if (b < 0) return 0;
  if (a == 0) return 0;
  long long int res = 1;
  while (b) {
    if (b & 1) {
      res = (1ll * res * a) % md;
    }
    a = (1ll * a * a) % md;
    b >>= 1;
  }
  return res;
}
long long int poww(long long int a, long long int b) {
  if (b < 0) return 0;
  if (a == 0) return 0;
  long long int res = 1;
  while (b) {
    if (b & 1) {
      res = (1ll * res * a);
    }
    a = (1ll * a * a);
    b >>= 1;
  }
  return res;
}
void ainp(long long int arr[], long long int n) {
  for (long long int i = 1; i <= n; i++) cin >> arr[i];
}
void disp(long long int arr[], long long int n) {
  for (long long int i = 1; i <= n; i++) cout << arr[i] << " ";
  cout << "\n";
}
void dispv(vector<long long int> &v) {
  for (long long int i = 0; i < v.size(); i++) cout << v[i] << " ";
  cout << "\n";
}
long long int divide(long long int a, long long int b, long long int md) {
  long long int rr = a * (poww(b, md - 2, md));
  rr %= md;
  return rr;
}
const long long int size = 2e5 + 2;
vector<pair<long long int, long long int> > d;
vector<long long int> ans[size];
long long int dis[size];
long long int n, dinp;
void printans(long long int par) {
  for (long long int child : ans[par]) {
    cout << par << " " << child << "\n";
    printans(child);
  }
}
bool fnn(pair<long long int, long long int> &a,
         pair<long long int, long long int> &b) {
  return a > b;
}
signed main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  cout.tie(NULL);
  fun();
  cin >> n;
  for (long long int i = 1; i <= n; i++)
    cin >> dinp, d.push_back(make_pair(dinp, 2 * i - 1));
  sort(d.begin(), d.end(), fnn);
  dis[1] = d[0].second;
  for (long long int i = 1; i < n; i++) {
    ans[d[i - 1].second].push_back(d[i].second);
    dis[i + 1] = d[i].second;
  }
  for (long long int i = 0; i < n; i++) {
    long long int which = dis[d[i].first + i];
    ans[which].push_back(d[i].second + 1);
    if (dis[d[i].first + i + 1] == 0) dis[d[i].first + i + 1] = d[i].second + 1;
  }
  printans(d[0].second);
  return 0;
}
