#include <bits/stdc++.h>
#define rep(i,n) for(int i=0;i<(int)(n);i++)
using namespace std;
using ll = long long ;
using P = pair<int,int> ;
using pll = pair<long long,long long>;
constexpr int INF = 1e9;
constexpr long long LINF = 1e17;
constexpr int MOD = 1000000007;


//1-indexedに注意！！！
template<class T>
struct BIT{
    private:
    int n;
    vector<T> bit;
    
    public:
    BIT(int n):n(n){
        bit.resize(n+1);
    }
    
    T sum(int i){
        T res = 0;
        while(i > 0){
                res += bit[i];
                i -= i&-i;
        }
        return res;
    }
    
    void add(int i,T val){
        while(i <= n){
                bit[i] += val;
                i += i&-i;
        }
    }
};

int main(){
    int n;
    cin >> n;
    vector<int> m(n);
    rep(i,n) cin >> m[i];
    ll ans = 0;
    BIT<ll> bit(n);
    rep(i,n){
        bit.add(m[i],1);
        ans += (i+1) - bit.sum(m[i]);
    }
    cout << ans << endl;
    return 0;
}