func_code_string: #include <bits/stdc++.h>   using namespace std;   mt19937_64 mrand(chrono::steady_clock::now().time_since_epoch().count());   int a[105], vis[105];   vector<int> v[105];   int main() {     int n;     cin >> n;     for (int i = 1; i <= 2 * n; ++i) cin >> a[i];     int ans = 0;     for (int i = 1; i <= 2 * n; ++i) {       if (vis[a[i]]) continue;       vis[a[i]] = 1;       for (int j = i + 1; a[j] != a[i]; ++j)         if (!vis[a[j]]) ++ans;     }     cout << ans <<   n ;   }   