#include <bits/stdc++.h>   using namespace std;   int n;   vector<int> a;   int was[100100];   int t[100100];   int main() {     ios_base::sync_with_stdio(0);     cin.tie(0);     cout.tie(0);     cin >> n;     for (int i = 1; i <= 2 * n; i++) {       int x;       cin >> x;       a.push_back(x);     }     vector<int> ans;     int cnt = 0;     for (int i = 0; i < 2 * n; i++) {       if (!was[a[i]]) {         t[a[i]] = i;         ans.push_back(a[i]);         was[a[i]] = true;       } else {         was[a[i]] = true;         cnt += i - t[a[i]] - 1;         ans.insert(ans.begin() + t[a[i]] + 1, a[i]);         for (int j = 0; j < ans.size(); j++) {           t[ans[j]] = j;         }       }     }     cout << cnt;     return 0;   }   