#include <bits/stdc++.h>
using namespace std;
const int maxn = 3e5 + 10;
int n, b[maxn];
pair<int, int> a[maxn];
int main() {
  scanf("%d", &n);
  for (int i = 1; i <= n; i++) {
    scanf("%d", &a[i].first);
    a[i].second = i;
  }
  sort(a + 1, a + 1 + n);
  reverse(a + 1, a + 1 + n);
  for (int i = 1; i <= n; i++) {
    b[i] = a[i].second * 2 - 1;
    if (i > 1) printf("%d %d\n", b[i], b[i - 1]);
  }
  int res, cur = n, des;
  for (int i = 1; i <= n; i++) {
    res = a[i].second * 2;
    des = i + a[i].first - 1;
    if (des >= cur) {
      b[++cur] = res;
      printf("%d %d\n", res, b[cur - 1]);
    } else
      printf("%d %d\n", res, b[des]);
  }
}
