Tunnels

#include <bits/stdc++.h>

using namespace::std;

ifstream fin("input.txt");

int main()
{
    int n, m, t1, t2;
    cin >> n >> m;
    vector<pair<int, int> > inout(n + 1);
    for (int i = 0; i < m; i++) {
        cin >> t1 >> t2;
        inout[t1].first++;
        inout[t2].second++;
    }

    int answ = 0;
    for (int i = 1; i <= n; i++) {
        answ += abs(inout[i].first - inout[i].second);
    }
    answ /= 2;

    cout << answ << "\n";
}

Test 1

Group: 1

Verdict: ACCEPTED

Test 2

Group: 1

Verdict: ACCEPTED

Test 3

Group: 1

Verdict: ACCEPTED

Test 4

Group: 1

Verdict: ACCEPTED

Test 5

Group: 1

Verdict: ACCEPTED

Test 6

Group: 2

Verdict: ACCEPTED

Test 7

Group: 2

Verdict: ACCEPTED

Test 8

Group: 2

Verdict: ACCEPTED

Test 9

Group: 2

Verdict: ACCEPTED

Test 10

Group: 2

Verdict: ACCEPTED

Test 11

Group: 3

Verdict: ACCEPTED

Test 12

Group: 3

Verdict: ACCEPTED

Test 13

Group: 3

Verdict: ACCEPTED

Test 14

Group: 3

Verdict: ACCEPTED

Test 15

Group: 3

Verdict: ACCEPTED