#include<stdio.h>
#define INFTY 2000000000
#define MAX 200000

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

long long merge(int A[], int left, int mid,int right)
{
	long long count = 0;
	int n1 = mid - left;
	int n2 = right - mid;
	int i,j,k;
	for(i = 0; i < n1; i++){
		L[i] = A[left + i];
	}
	for(i = 0; i < n2; i++){
		R[i] = A[mid + i];
	}
	L[n1] = INFTY;
	R[n2] = INFTY;
	i = 0;
	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)
{
	long long v1,v2,v3;
	if(left + 1 < right){
		int 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(void)
{
	int i, n;
	scanf("%d",&n);
	int S[200000];
	for(i=0; i<n; i++){
		scanf("%d", &S[i]);
	}
	long long ans = mergeSort(S, 0, n); 
	printf("%lld\n", ans);
	return 0;
}



