func_code_string: #include <bits/stdc++.h>   using namespace std;   int arr[100002];   int main() {     int i, n, ans = 0, mm = 0;     cin >> n;     n = n << 1;     for (i = 0; i < n; i++) {       int a;       scanf( %d , &a);       ans = ans - arr[a];       arr[a] = arr[a] ^ 1;       ans += arr[a];       mm = max(mm, ans);     }     cout << mm << endl;     return 0;   }   