#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;
}
