#include <bits/stdc++.h>

using namespace std;
typedef long long ll;
typedef long double ld;

int main() {
#ifdef LOCAL
    freopen("input.txt", "r", stdin);
    freopen("output.txt", "w", stdout);
#endif // LOCAL
    ios::sync_with_stdio(0), cin.tie(0), cout.tie(0);

    int n;
    cin >> n;

    int a[n], b[n], c[n];

    for (int i = 0; i < n; ++i) {
        cin >> a[i];
        b[i] = a[i];
    }
    sort(b, b + n);

    vector<pair<int, int>> res;

    auto reshuf = [&](int l, int r) {
                      int m = (l + r + 1) / 2;

                      for (int i = l; i < m; ++i) {
                          c[l + 1 + (i - l) * 2] = b[i];
                      }
                      for (int i = m; i <= r; ++i) {
                          c[l + (i - m) * 2] = b[i];
                      }

                      for (int i = l; i <= r; ++i)
                          b[i] = c[i];
                  };

    mt19937 rnd(chrono::steady_clock::now().time_since_epoch().count());

    vector<pair<int, int>> qwerty;

    reshuf(0, n - 1);
    qwerty.push_back({0, n - 1});

    int ddd = 1000;

    for (int i = 0; i < ddd; ++i) {
        int l = rnd() % n, r = rnd() % n;
        if (l == r) continue;

        if (l > r) swap(l, r);

        reshuf(l, r);
        qwerty.push_back({l, r});
    }

    reshuf(0, n - 1);
    qwerty.push_back({0, n - 1});

    auto shuf = [&](int l, int r) {
                    int t;
                    for (int i = l + 1; i <= r; i += 2)
                        c[(i - l) / 2] = a[i], t = (i - l) / 2;

                    for (int i = l; i <= r; i += 2)
                        c[t + 1 + (i - l) / 2] = a[i];

                    for (int i = 0; i < r - l + 1; ++i)
                        a[l + i] = c[i];
                };

    int r = 0;

    for (int i = 0; i < n; ++i) {
        while (a[i] != b[i]) {
            int j = i + 1;

            while (n - 1 <= 2 * j - i - 1 && !(b[j] == a[i] || b[j] == a[i + 1])) j++;

            if (b[j] == a[i]) {
                qwerty.push_back({i, 2 * j - i - 1});
                reshuf(i, 2 * j - i - 1);
                continue;
            } else if (b[j] == a[i + 1]) {
                qwerty.push_back({i, 2 * j - i - 1});
                reshuf(i, 2 * j - i - 1);
                res.push_back({i, i + 1});
                swap(a[i], a[i + 1]);
                continue;
            }

            j = i + 1;
            while (a[j] != b[i]) j++;
            if ((i + j) % 2 == 1)
                r = 0, res.push_back({i, j + r}), shuf(i, j + r);
            else
                r = 0, res.push_back({i + 1, j + r}), shuf(i + 1, j + r);
        }
    }

    reverse(qwerty.begin(), qwerty.end());

    for (auto i: qwerty)
        res.push_back(i);

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

    if (res.size() > 15000)
        return -1;

    for (auto i: res)
        cout << i.first + 1 << " " << i.second + 1 << "\n";
    return 0;
}