#include<bits/stdc++.h>
#define STIZE(x) fprintf(stderr, "STIZE%d\n", x);
#define PRINT(x) fprintf(stderr, "%s = %d\n", #x, x);
#define NL(x) printf("%c", " \n"[(x)]);
#define lld long long
#define pii pair<int,int>
#define pb push_back
#define fi first
#define se second
#define mid (l+r)/2
#define endl '\n'
#define all(a) begin(a),end(a)
#define sz(a) int((a).size())
#define LINF 1000000000000000LL
#define INF 1000000000
#define EPS 1e-9
using namespace std;
#define MAXN 200010
int n, s[MAXN], m, x[3*MAXN], y[3*MAXN], p[3*MAXN], q[3*MAXN], idxx, idx[MAXN];
bool pos[MAXN];
void DFS(int node) {
pos[node] = 1;
if(!pos[s[node]]) DFS(s[node]);
}
void DFS1(int node) {
pos[node] = 1;
if(!pos[s[node]]) {
p[idxx] = node;
q[idxx] = s[node];
idxx++;
DFS1(s[node]);
}
}
bool check(int key) {
for(int i = 0; i < key; i++) swap(s[x[i]], s[y[i]]);
for(int i = 0; i < n; i++) pos[i] = 0;
int cnt = 0;
for(int i = 0; i < n; i++) {
if(!pos[i]) DFS(i), cnt++;
}
return n-cnt <= key;
}
int findSwapPairs(int N, int S[], int M, int X[], int Y[], int P[], int Q[]) {
n = N, m = M; int rez = M, l = 1, r = M;
bool sorted = 1;
for(int i = 0; i < N; i++) if(S[i] != i) sorted = 0;
for(int i = 0; i < M; i++) x[i] = X[i], y[i] = Y[i];
if(sorted) return 0;
for(int i = 0; i < N; i++) s[i] = S[i], idx[s[i]] = i;
while(l <= r) {
if(check(mid)) rez = mid, r = mid-1;
else l = mid+1;
for(int i = 0; i < n; i++) s[i] = S[i];
}
for(int i = 0; i < rez; i++) swap(s[X[i]], s[Y[i]]);
for(int j = 0; j < N; j++) pos[j] = 0;
for(int j = 0; j < N; j++) {
if(!pos[j]) DFS1(j);
}
for(int j = 0; j < idxx; j++) P[j] = p[j], Q[j] = q[j];
for(int j = idxx; j < rez; j++) P[j] = 0, Q[j] = 0;
for(int i = 0; i < rez; i++) {
swap(S[X[i]], S[Y[i]]);
swap(idx[S[X[i]]], idx[S[Y[i]]]);
P[i] = idx[s[P[i]]], Q[i] = idx[s[Q[i]]];
swap(S[P[i]], S[Q[i]]);
swap(idx[S[P[i]]], idx[S[Q[i]]]);
}
return rez;
}
