#pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx")
#pragma GCC optimize 03
#pragma GCC optimize("unroll-loops")

#include <iostream>
#include <algorithm>
#include <iterator>
#include <cmath>
#include <ctime>
#include <vector>
#include <deque>
#include <queue>
#include <set>
#include <map>
#include <stack>
#include <string>
#include <random>
#include <numeric>
#include <unordered_set>

typedef long long ll;
typedef long double lb;

#define fast ios_base::sync_with_stdio(false); cin.tie(0); cout.tie(0);
#define file_in freopen("input.txt", "r", stdin);
#define file_in_out freopen("knapsack.in", "r", stdin); freopen("knapsack.out", "w", stdout);
#define mp make_pair
#define pii pair<int, int>
#define all(x) (x).begin(), (x).end()
#define fi first
#define se second

using namespace std;

template<typename T>
istream& operator>>(istream &in, vector<T> &v) {
    for (auto &it : v) {
        in >> it;
    }
    return in;
}

template<typename T>
ostream& operator<<(ostream &out, vector<T> &v) {
    if (!v.empty()) {
        out << v.front();
        for (int i = 1; i < v.size(); ++i) {
            out << " " << v[i];
        }
    }
    return out;
}

int main() {
    fast
//  file_in
//  file_in_out

    int n, j;
    cin >> n;
    vector<int> a(n);
    cin >> a;
    vector<int> b = a;
    map<pii, vector<int>> cnt;
    map<int, int> cntt;
    sort(all(b));
    vector<pii> ans;
    for (int i = 0; i < n; ++i) cnt[mp(a[i], b[i])].push_back(i);
    for (int i = 0; i < n; ++i) {
        if (!cntt[i] && a[i] != b[i] && cnt[mp(b[i], a[i])].size()) {
            j = cnt[mp(b[i], a[i])][cnt[mp(b[i], a[i])].size() - 1];
            swap(a[i], a[j]);
            ans.emplace_back(i + 1, j + 1);
            cnt[mp(b[i], a[i])].pop_back();
            ++cntt[i]; ++cntt[j];
        }
    }
    for (int i = 1; i < n; ++i) if (a[i] < a[i - 1]) {cout << "No"; return 0;}
    cout << "Yes" << "\n" << ans.size() << "\n";
    for(auto el : ans) cout << el.fi << " " << el.se << endl;
    return 0;
}