//
// Created by Ayan Ginet on 03.04.2018.
//
#include <iostream>
#include <cmath>
#include <cstdio>
#include <vector>
#include <algorithm>
#include <map>


using namespace std;

bool myComparison(const pair<long long,pair<long long, long long>> &a,
                  const pair<long long, pair<long, long>> &b)
{
    return a.second.first < b.second.first;
}

bool cmp(const pair<long, long> &a,
                  const pair<long, long> &b)
{
    return a.first < b.first;
}

vector<int> swap( vector<int> &nums, int first, int second){
    if(second >= nums.size()) return nums;
    int buf = nums[first];
    nums[first] = nums[second];
    nums[second] = buf;
    return nums;
}

int minSwap( vector<int> &nums, int i, int n){
    if(i > n) return 0;

    if(nums[i] == nums[i+1])
    return minSwap( nums, i + 2,  n);

    nums = swap(nums, i, i + 1);
    int a = 1;
    a += minSwap(nums, i + 1, n);

    nums = swap(nums, i , i + 1);
    nums = swap(nums, i + 1 , i + 2);
    int b = 1 + minSwap(nums, i + 1, n);

    return min(a,b);

}



int main(){
    std::ios::sync_with_stdio(false);
    cin.tie(nullptr);

   int n;
   cin >> n;
   
   vector<int> nums;

   for(int i = 0; i < 2 * n; i++){
       int buf;
       cin >> buf;
       nums.push_back(buf);
   }

    cout << minSwap(nums, 0, nums.size());

}