func_code_string: #include <bits/stdc++.h>   using namespace std;   bool s[100005];   int main() {     int n;     cin >> n;     n *= 2;     int ans = 0, rst = 0;     ;     while (n--) {       int tmp;       cin >> tmp;       if (s[tmp])         ans -= 1;       else         s[tmp] = 1, ans++;       rst = max(rst, ans);     }     cout << rst << endl;     return 0;   }   