#include <bits/stdc++.h>
using namespace std;

using ll = long long;
using ld = long double;

#define rep(i, n) for(ll i=0; i<(n); ++i)
#define rrep(i, n) for(ll i=(n)-1, i>=0; --i)
#define all(a) (a).begin(),(a).end()
#define rall(a) (a).rbegin(),(a).rend()
#define debug(x) cerr << #x << " : " << (x) << '\n'

ll const INF = 2e18;

// 4近傍 右上左下
const int dx4[4] = {1,0,-1,0};
const int dy4[4] = {0,1,0,-1};

// 8近傍
const int dx8[8] = {1,1,0,-1,-1,-1,0,1};
const int dy8[8] = {0,1,1,1,0,-1,-1,-1};

// grid内ならtrueを返し、gridから出るときはfalse
bool in_grid(ll H, ll W, ll x, ll y){
    return(0<=x&&x<H&&0<=y&&y<W);
}

template <typename T1, typename T2>
ostream& operator<<(ostream& os, const pair<T1, T2>& p) {
    return os << "(" << p.first << "," << p.second << ")";
}

template <typename T>
void print_vector(const std::vector<T>& x) {
    std::cerr << "[";
    for (size_t i = 0; i < x.size(); ++i) {
        std::cerr << x[i];
        if (i != x.size() - 1) std::cerr << " ";
    }
    std::cerr << "]" << std::endl;
}

template <typename T>
void print_vector2(const std::vector<std::vector<T>>& x) {
    for (const auto& row : x) {
        std::cerr << "[";
        for (size_t j = 0; j < row.size(); ++j) {
            std::cerr << row[j];
            if (j != row.size() - 1) std::cerr << " ";
        }
        std::cerr << "]" << std::endl;
    }
}



int main() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
freopen("random_20.in","r",stdin); 
freopen("random_20.out","w",stdout); 
    ll N; cin >> N;
    vector<ll> A(N);
    vector<ll> inv_A(N); // inv_A[val] = idx : A[idx] = valとなる
    for(ll i=0; i<N; i++){
        cin >> A[i];
        A[i]--;
        inv_A[A[i]] = i;
    }
    vector<pair<ll, ll>> ans;
    for(ll i=0; i<N-1; i++){
        if(A[i] == i) continue;
        ll target = inv_A[i];
        ans.emplace_back(i, target);
        swap(inv_A[A[i]], inv_A[A[target]]);
        swap(A[i], A[target]);
    }

    ll M = ans.size();
    cout << M << endl;
    for(ll i=0; i<M; i++){
        cout << ans[i].first+1 << " " << ans[i].second+1 << '\n';
    }

    return 0;
}