#include<bits/stdc++.h>
#define all(v) v.begin(), v.end()
#define endl "\n"
using namespace std;

const int N = 1e5 + 10;

int a[N], deg[N];

int n;

vector<int> adj[N];

int32_t main() {
  #define task ""

  cin.tie(0) -> sync_with_stdio(0);

  if (fopen("task.inp", "r")) {
    freopen("task.inp", "r", stdin);
    freopen("task.out", "w", stdout);
  }

  if (fopen(task".inp", "r")) {
    freopen (task".inp", "r", stdin);
    freopen (task".out", "w", stdout);
  }

  cin >> n;

  for(int i = 1; i <= n; i++) cin >> a[i];

  for(int i = 1; i <= n; i++) for(int j = i + 1; j <= n; j++) if (a[i] > a[j]) {
    deg[j]++;
    adj[i].push_back(j);
  }

  queue<int> q, free;
  for(int i = 1; i <= n; i++) if (deg[i] == 0) {
    if (adj[i].empty()) free.push(i);
    else q.push(i);
  }

  auto del = [&] (int u) {
    for(int &v : adj[u]) {
      deg[v]--;
      if (deg[v] == 0) {
        if (adj[v].empty()) free.push(v);
        else q.push(v);
      }
    }
  };

  vector<pair<int, int> > ans;

  while (1) {
    if (q.size() >= 2) {
      int x = q.front(); q.pop();
      int y = q.front(); q.pop();
      ans.emplace_back(a[x], a[y]);
      del(x);
      del(y);
    }
    else if (q.size() == 1) {
      int x = q.front(); q.pop();
      int y = free.front(); free.pop();
      ans.emplace_back(a[x], a[y]);
      del(x);
    }
    else {
      if (free.empty()) break;
      int x = free.front(); free.pop();
      if (free.empty()) {
        ans.emplace_back(a[x], a[x]);
        break;
      }
      int y = free.front(); free.pop();
      ans.emplace_back(a[x], a[y]);
    }
  }

  cout << ans.size() << endl;

  for(auto &[x, y] : ans) cout << x << " " << y << endl;
}