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

#define fastIO ios_base::sync_with_stdio(false); cin.tie(nullptr);  cout.tie(nullptr);

static const int SIZE = 2000000 + 7;

void input(int* arr, int &n) {
	cin >> n;
	for (int i = 0; i < n; i++) {
		cin >> arr[i];
	}
}

long long merge(int* arr, int* left, int* right, int n) {
	int i = 0;
	int j = 0;
	long long res = 0;

	int index = 0;
	while (i < n / 2 && j < n / 2 + n % 2) {
		if (left[i] <= right[j]) {
			arr[index++] = left[i++];
		}
		else {
			res += n / 2 - i;
			arr[index++] = right[j++];
		}
	}

	while (i < n / 2) {
		arr[index++] = left[i++];
	}

	while (j < n / 2 + n % 2) {
		arr[index++] = right[j++];
	}

	delete[] left;
	delete[] right;
	return res;
}

long long countInversions(int* arr, int n) {
	if (n <= 1) return 0;

	int* left = new int[n / 2];
	int* right = new int[n / 2 + n % 2];

	for (int i = 0; i < n / 2; i++) {
		left[i] = arr[i];
	}

	for (int i = 0; i < n / 2 + n % 2; i++) {
		right[i] = arr[n / 2 + i];
	}

	long long leftRes = countInversions(left, n / 2);
	long long rightRes = countInversions(right, n / 2 + n % 2);

	return leftRes + rightRes + merge(arr, left, right, n);
}

int n;
int arr[SIZE];

int main() {
	fastIO

	input(arr, n);
	cout << countInversions(arr, n) << endl;

	return 0;
}