#include <bits/stdc++.h>
using namespace std;
long long int paletta_sort(int N, int* V){
    vector<int> pari;
    vector<int> dispari;
    int ans =0;
    for(int i =0; i<N; i++){
        if (V[i]%2==0){
            if (i%2!=0) return -1;
            pari.push_back(V[i]);
        }
        else{
            if (i%2==0) return -1;
            dispari.push_back(V[i]);
        }
    }
    
    int maxD = *(dispari.end()-1);
    int maxP = *(pari.end()-1);
    for (int i =0; i<dispari.size(); i++){
        for (int j =0; j<i; j++){
            if (dispari[j]>dispari[i]) ans++;
        }
    }
    for (int i =0; i<pari.size(); i++){
        for (int j =0; j<i; j++){
            if (pari[j]>pari[i]) ans++;
        }
    }
    return ans;
}