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

template<typename T>
class BIT{
  public:
    int N;
    vector<T> data;
    BIT(T _N):N(_N){
        data.assign(N+1, 0);
    };
    
    // a is 1-indexed
    void add(int a, T w){
        for(int x = a; x <= N; x += x & -x)data[x] += w;
    }
    // 1-indexed sum of prefix [0, a]
    T sum(int a){
        T res = 0;
        for(int x = a; x > 0; x -= x & -x)res += data[x];
        return res;
    }
    // 1-indexed sum of range [l, r]
    T sum(int l, int r){return sum(r) - sum(l-1);}

    // 0-indexed add
    void add0(int a, T w){add(a + 1, w);}
    // 0-indexed sum
    T sum0(int a){return sum(a + 1);}
    // 0-indexed sum of range
    T sum0(int l, int r){return sum0(r) - sum0(l-1);}
    // show the value
    void debug(){print(data);}
};

int main()
{
	int N;
	cin >> N;
	vector<pair<int, int>> ap( N );
	for( int i = 0; i < N; i++ ) {
		int P;
		cin >> P;
		ap[i] = make_pair( P, i );
	}

	sort( ap.begin(), ap.end() );
	vector<int> b( N );
	for( int i = 0; i < N; i++ ) b[ ap[i].second ] = i;
	BIT<long long> c( N );
	long long ans = 0;
	for( int i = 0; i < N; i++ ) {
		ans += i - c.sum0( b[i] );
		c.add0( b[i], 1 );
	}

	cout << ans << endl;
}