#include<bits/stdc++.h>
using namespace std;
using ll = long long;

template<class T>bool chmax(T &a, const T &b) { if (a<b) { a=b; return 1; } return 0; }
template<class T>bool chmin(T &a, const T &b) { if (b<a) { a=b; return 1; } return 0; }

#define FOR(i,a,b) for(ll i=(a);i<(b);++i)
#define ALL(v) (v).begin(), (v).end()
#define p(s) cout<<(s)<<endl
#define p2(s, t) cout << (s) << " " << (t) << endl
#define br() p("")
#define pn(s) cout << (#s) << " " << (s) << endl

ll cnt = 0;

void bubble_sort(vector<ll> &A){
    ll N = A.size();    
    // iまで見る
    for(int i=N-1; i>=0; i--){
        FOR(j, 0, i){
            if(A[j] > A[j+1]){
                cnt++;
                swap(A[j], A[j+1]);
            }
        }
    }
}

int main(){
    cin.tie(0);
    ios::sync_with_stdio(false);

    // input
    ll N;
    cin >> N;

    vector<ll> A(N);
    FOR(i, 0, N){
        cin >> A.at(i);
    }

    bubble_sort(A);
    p(cnt);
    
    return 0;
}