func_code_string: #include <bits/stdc++.h>   int ar[100000];   using namespace std;   int main() {     int n;     cin >> n;     int c = 0, ans = 0;     int r;     for (int i = 0; i < 2 * n; i++) {       cin >> r;       if (ar[r]) {         ar[r] = 0;         c--;       } else {         c++;         ar[r] = 1;       }       if (ans < c) ans = c;     }     cout << ans << endl;   }   