Tunnels

input/code.cpp: In function 'int main()':
input/code.cpp:42:12: warning: unused variable 'c' [-Wunused-variable]
     ll a,b,c,d,e;
            ^
input/code.cpp:42:14: warning: unused variable 'd' [-Wunused-variable]
     ll a,b,c,d,e;
              ^
input/code.cpp:42:16: warning: unused variable 'e' [-Wunused-variable]
     ll a,b,c,d,e;
                ^

#include <bits/stdc++.h>
using namespace std;

#define rep(i, a, b) for(int i = a; i < (b); ++i)
#define per(i, b, a) for(int i = b - 1; i >= a; i--)
#define trav(a, x) for(auto& a : x)
#define all(x) x.begin(), x.end()
#define sz(x) (int)(x).size()
typedef long long ll;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;
typedef vector<int> vi;
typedef vector<ll> vl;
typedef long double ld;
typedef unsigned long long ull;

unsigned seed = chrono::system_clock::now().time_since_epoch().count();
mt19937 eng(seed);

ll random2(){
    return (1ll << 31ll)*eng()+eng();
}

ll n,m,k,q,T;

const ll big = 1000000007;
const ll big2 = 1000000009;
const ll mod =  998244353;

const int MAXN = 100006;

int indeg[MAXN] = {0};
int outdeg[MAXN] = {0};

int main() {
    ios_base::sync_with_stdio(0);
    cin.tie(0);

   // freopen("fhc.txt","r",stdin);
   // freopen("autput.txt","w",stdout);

    ll a,b,c,d,e;

    cin >> n >> m;
    int ans = 0;
    rep(c1,0,m){
        cin >> a >> b;
        a--;
        b--;
        indeg[b]++;
        outdeg[a]++;
    }
    rep(c1,0,n){
        ans += max(0, outdeg[c1]-indeg[c1]);
    }
    cout << ans << "\n";
    return 0;
}

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