qcS4bE - Online IDE & Debugging Tool

#include <bits/stdc++.h>
#define FOR(i, a, b) for(int i = (a), _b = (b); i <= _b; ++i)
#define fi first
#define se second
#define el "\n"
#define pb push_back
#define sz(a) (int)a.size()
#define FILL(a, x) memset(a, x, sizeof(a))

using namespace std;
typedef long long ll;
typedef pair<string, string> ii;
const int N = (int)1e6+3;
ii a[60];
int n;
ll ans;

int main()
{
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);    cout.tie(NULL);
    freopen("bff.inp", "r", stdin);
    freopen("bff.out", "w", stdout);
    cin >> n;
    FOR(i, 1, n) cin >> a[i].fi >> a[i].se;
    FOR(i, 1, n)
     FOR(j, 1, n)
      if (i != j && a[i].fi == a[j].se) ++ans;
    cout << ans;
    return 0;
}