ЗОШ конденсация OK

#include <iostream>
#include <cmath>
#include <vector>
#include <queue>
#include <algorithm>
#include <string>
#include <stack>
#include <set>
#include <map>
#define pii pair <int,int>
using namespace std;
using ll = long long;
using ld = long double;
void cv(vector <int> &v){
    for (auto x: v) cout<<x<<' ';
    cout<<"\n";
}

void cvl(vector <ll> &v){
    for (auto x: v) cout<<x<<' ';
    cout<<"\n";
}


void cvv(vector <vector <int> > &v){
    for (auto x: v) cv(x);
    cout<<"\n";
}
int n,m;
vector <vector<int>>G;
vector <vector<int>> reG;
const int wh = 0, gr = 1, bl = 2;
vector <int> clr;
vector <int> tp;


bool paint = 0;
int cmp_num = 0;

vector <int> comp;

void dfs(int v, int pr){

    clr[v] = gr;
    if (paint) comp[v] = cmp_num;
    for (int u: G[v]){
        if (u == pr) continue;
        else if (clr[u] == wh){
            dfs(u, v);
        }

    }
    clr[v] = bl;
    if (!paint) tp.push_back(v);
}

//void re


int main()
{
    ios::sync_with_stdio(0);
	cin.tie(0);
	cout.tie(0);
	cin>>n>>m;
	G.resize(n);
	reG.resize(n);
	clr.assign(n, wh);
	comp.resize(n,-1);
	for (int i=0;i<m;++i){
        int a,b;
        cin>>a>>b;
        a--; b--;
        G[a].push_back(b);
        reG[b].push_back(a);
	}

	for (int i = 0;i<n;++i){
        if (clr[i] == wh){
            dfs(i, -1);
        }
	}

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

	paint = 1;
	G = reG;
	clr.assign(n, wh);

	for (int i=0;i<n;++i){

        if (clr[tp[i]] == wh){
            dfs(tp[i], -1);
            cmp_num++;
        }
	}

	set <pii> ans;
	for (int i = 0;i<n;++i){

        for (int j=0;j<G[i].size();++j){

            if (comp[G[i][j]] != comp[i]) {

                //ans.insert( {min(i,G[i][j]), max(i, G[i][j])} );
                ans.insert( { min( comp[i], comp[G[i][j]]) , max(comp[i], comp[G[i][j]]) } );
            }

        }
	}
	cout<<ans.size()<<"\n";
}

/*
8 11
1 2
2 1
2 3
3 4
4 5
5 3
5 6
6 4
7 8
8 7
7 1

8 10
1 2
2 1
2 3
3 4
4 5
5 3
5 6
6 4
7 8
8 7

4 4
2 1
3 2
2 3
4 3

6 8
1 2
2 1
2 3
3 4
4 5
5 3
5 6
6 4


*/