// mc4b.cpp : Defines the entry point for the console application.
//
#include <iostream>
#include <set>
#include <stack>
using namespace std;


struct NOD
{
    int index;
    int val;
};

int n, i, a[105000];
bool instack[1000500];

stack<int> stiva;

int main()
{
    cin >> n;
    for (i = 1; i <= 2 * n; i++)
    {
        cin >> a[i];
    }

    int cnt = 0;
    for (i = 1; i <= 2 * n; i++)
    {
        if (instack[a[i]])
        {
            while (!stiva.empty() && stiva.top() != a[i])
            {
                cnt++;
                instack[stiva.top()] = false;
                stiva.pop();
            }
            instack[stiva.top()] = false;
            stiva.pop();
            
        }
        else {
            stiva.push(a[i]);
            instack[a[i]] = true;
        }
        
    }
    cout << cnt;





}