#include <stdio.h>
#include <stdlib.h>

#define MAX 200000
#define INF 2000000000

int L[MAX/2 + 2], R[MAX/2 + 2];

long long merge(int *A, int left, int mid, int right)
{
	int i, j, k;
	long long count = 0;
	int n1 = mid - left;
	int n2 = right - mid;
	for(i = 0; i < n1; i++)
		L[i] = A[left+i];
	for(i = 0; i < n2; i++)
		R[i] = A[mid+i];
	L[n1] = R[n2] = INF;
	i = j = 0;
	for(k = left; k < right; k++) {
		if(L[i] <= R[j]) {
			A[k] = L[i++];
		}
		else {
			A[k] = R[j++];
			count += n1 - i;
		}
	}
	return count;
}

long long mergeSort(int *A, int left, int right)
{
	int mid;
	long long v1, v2, v3;
	if(right - left > 1) {
		mid = (left + right) / 2;
		v1 = mergeSort(A, left, mid);
		v2 = mergeSort(A, mid, right);
		v3 = merge(A, left, mid, right);
		return v1 + v2 + v3;
	}else {
		return 0;
	}
}

int main()
{
	int i, n;
	int *A;
	long long ans;
	scanf("%d", &n);

	A = (int *)malloc(sizeof(int) * n);

	for(i = 0; i < n; i++)
		scanf("%d", &A[i]);

	ans = mergeSort(A, 0, n);

	printf("%lld\n", ans);
  return 0;
}