/*
Observation:
if we can do it in N turns, we can do it in N + 1
*/
#include <bits/stdc++.h>
using namespace std;
#define f first
#define s second
#define pb push_back
#define ar array
#define all(x) x.begin(), x.end()
#define siz(x) (int)x.size()
#define FOR(x, y, z) for(int x = (y); x < (z); x++)
#define ROF(x, z, y) for(int x = (y-1); x >= (z); x--)
#define F0R(x, z) FOR(x, 0, z)
#define R0F(x, z) ROF(x, 0, z)
#define trav(x, y) for(auto&x:y)
using ll = long long;
using vi = vector<int>;
using vl = vector<long long>;
using pii = pair<int, int>;
using vpii = vector<pair<int, int>>;
template<class T> inline bool ckmin(T&a, T b) {return b < a ? a = b, 1 : 0;}
template<class T> inline bool ckmax(T&a, T b) {return b > a ? a = b, 1 : 0;}
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
const char nl = '\n';
const int mxN = 2e5 + 10;
const int MOD = 1e9 + 7;
const long long infLL = 1e18;
int findSwapPairs(int n, int* s, int M, int* x, int *y, int *p, int *q){
int l = 0, r = M + 1;
vpii ans;
while(l < r){
int m = l + r; m = m / 2;
vi pos(n);
vi cur(n);
vpii ops;
F0R(i, n){
cur[i] = s[i];
}
F0R(i, m){
swap(cur[x[i]], cur[y[i]]);
}
//cout << m << endl;
//F0R(i, n){
// cout << cur[i] << ' ';
//}
//cout << endl;
F0R(i, n){
pos[cur[i]] = i;
}
F0R(i, n){
if(cur[i] != i){
int x = cur[i];
// whats currently at the spot we want
int z = pos[i];
// the pos of our current element
ops.pb({i, x});
cur[z] = x;
cur[i] = i;
pos[i] = i;
pos[x] = z;
}
}
if(siz(ops) <= m){
ans = ops;
r = m;
}
else{
l = m + 1;
}
}
vi pos(n);
vi cur(n);
vpii res;
F0R(i, n){
pos[s[i]] = i;
cur[i] = s[i];
}
F0R(i, siz(ans)){
//F0R(i, n){
// cout<<cur[i]<<' ';
//}
//cout << nl;
swap(pos[cur[x[i]]], pos[cur[y[i]]]);
swap(cur[x[i]], cur[y[i]]);
res.pb({pos[ans[i].f], pos[ans[i].s]});
//cout << ans[i].f << ' ' << ans[i].s << nl;
//cout << pos[ans[i].f] << ' ' << pos[ans[i].s] << nl;
swap(pos[ans[i].f], pos[ans[i].s]);
//assert(pos[cur[ans[i].f]]==ans[i].s);
swap(cur[pos[ans[i].f]], cur[pos[ans[i].s]]);
}
F0R(i, l){
if(i < res.size()){
p[i] = res[i].f; q[i] = res[i].s;
}
else{
p[i] = 0; q[i] = 0;
}
}
return l;
}
//int32_t main(){
// ios_base::sync_with_stdio(0); cin.tie(0);
// int N;
// cin >> N;
// int S[N];
// F0R(i, N){
// cin >> S[i];
// }
// int M;
// cin >> M;
// int X[M], Y[M];
// F0R(i, M){
// cin >> X[i] >> Y[i];
// }
// int P[M], Q[M];
// int res = findSwapPairs(N, S, M, X, Y, P, Q);
// cout << res << nl;
// F0R(i, res){
// cout << P[i] << ' ' << Q[i] << nl;
// }
// return 0;
//}
