#include<bits/stdc++.h>
#include<ext/pb_ds/assoc_container.hpp>
#include<ext/pb_ds/tree_policy.hpp>
using namespace std;
using namespace __gnu_pbds;

typedef int MYTYPE_INDEX; // index
typedef null_type MYTYPE_VALUE;

map<string,bool> M;

tree< 	MYTYPE_INDEX,
        MYTYPE_VALUE,
        less< MYTYPE_INDEX >,
        rb_tree_tag, // red black
        tree_order_statistics_node_update
        > TR;

const int maxn = 5e5 + 10;
int A[maxn];

int main() {
	int n;
	cin >> n;
	for (int i = 0; i < n; i++) {
		cin >> A[i];
	}
	long long ans = 0;

	for (int i = 0; i < n; i++) {
		int x = A[i];
		ans += TR.order_of_key(x); // 这里我能想到3种写法哦~~
		TR.insert(x);
	}
	cout << ans;

	return 0;
}