/*
*   ────────────── •✵•✵• ──────────────
* |         In The Name of *Allah*       |
*   ────────────── •✵•✵• ──────────────
*/

#ifndef ONLINE_JUDGE
#include "debug.h" 
#else
#define deb(x...)
#endif

#include <iostream>
#include <queue>
#include <map>
#include <set>
#include <math.h>
#include <vector>
#include <string.h>
#include <algorithm>

using namespace std;
typedef long long ll;
typedef long double ld;

#define pb push_back
#define si(x) (long long)x.size()
#define all(x) x.begin(), x.end()
const long long maxn = 2e5 + 10; 
long long n, a[maxn], b[maxn];

long long merge(long long a[], long long temp[], long long left, long long mid, long long right){
    long long inv_count = 0; 
    long long i = left;
    long long j = mid;  
    long long k = left; 
    while ((i <= mid - 1) && (j <= right)){
        if (a[i] <= a[j]){
            temp[k++] = a[i++];
        }
        else{
            temp[k++] = a[j++];
            inv_count = inv_count + (mid - i);
        }
    }
    while (i <= mid - 1){
        temp[k++] = a[i++];
    }
    while (j <= right){
        temp[k++] = a[j++];
    }
    for (i=left; i <= right; i++){
        a[i] = temp[i];
    }
    return inv_count;
}
long long _mergeSort(long long a[], long long temp[], long long left, long long right){
    long long mid, inv_count = 0;
    if (right > left){
        mid = (right + left)/2;
        inv_count  = _mergeSort(a, temp, left, mid);
        inv_count += _mergeSort(a, temp, mid+1, right);
        inv_count += merge(a, temp, left, mid+1, right);
    }
    return inv_count;
}
long long ans(long long a[], long long n){
    long long temp[n];
    return _mergeSort(a, temp, 0, n - 1);
}
void solve (){
    cin >> n;
    for (long long i = 0; i < n; i++){
        cin >> a[i];
        b[i] = a[i];
    }
    reverse(a, a + n);
    vector <long long> kom, lom;
    for (long long i = 0; i < n; i+= 2){
        kom.pb(a[i]);
    }
    for (long long i = 1; i < n; i+= 2){
        lom.pb(a[i]);
    }
    sort(all(lom)), sort(all(kom));
    long long j = 0;
    for (long long i = 0; i < n; i+= 2){
        a[i] = kom[j];
        ++ j;
    }
    // deb(kom), deb(lom);
    j = 0;
    for (long long i = 1; i < n; i+= 2){
        a[i] = lom[j];
        ++ j;
    }
    cout << ans(a, n);
}

int main () {
  ios_base :: sync_with_stdio(0), cin.tie(0), cout.tie(0);
  long long tc = 1;
  // cin >> tc;
  while (tc --) {
    solve();
  }
  return 0;
}
/* Thanks *Allah* */