//#include <atcoder/all>
#include <bits/stdc++.h>
using namespace std;
//using namespace atcoder;
using ll = long long;
#define all(A) A.begin(),A.end()
using vll = vector<ll>;
#define rep(i, n) for (long long i = 0; i < (long long)(n); i++)
using Graph = vector<vector<pair<ll, ll>>>;
Graph G;
vll dist;
vector<bool> seen;
struct fenwick_tree {
	ll n;
	vll bit;
	fenwick_tree(ll num) :bit(num + 1, 0) { n = num; }

	void add(ll i, ll w) {
		for (ll x = i+1; x <= n; x += x & -x) {
			bit[x-1] += w;
		}
	}

	ll sum(ll i) {
		ll ret = 0;
		for (ll x = i+1; x > 0; x -= x & -x) {
			ret += bit[x-1];
		}
		return ret;
	}

	ll sum(ll L, ll R) {
		return sum(R) - sum(L);
	}


};
ll TE(vll A) {
	ll res = 0;
	ll N = A.size();
	fenwick_tree fw(N);
	rep(i, N) {
		res += i - fw.sum(A[i]);
		fw.add(A[i], 1);
	}
	return res;
}
int main() {
    ll N;
    cin>>N;
    vll P(N);
    rep(i,N){
        cin>>P[i];
        P[i]--;
    }
    cout<<TE(P)<<endl;
}