#include<stdio.h>

const int maxn=1000001;
int A[maxn];
int count; 

void merge(int arr[], int left, int middle, int right){
	int i, j;
	int n1=middle-left+1, n2=right-middle;
	int L[n1], R[n2];
	for(i=0;i<n1;i++) L[i]=arr[left+i];
	for(j=0;j<n2;j++) R[j]=arr[middle+1+j];

	i=j=0;
	int k=left;
	while(i<n1 && j<n2)
		if(L[i]<=R[j]) arr[k++] = L[i++];
		else{
			arr[k++] = R[j++];
			count = count+n1-i;
		}
	while (i<n1)  arr[k++] = L[i++];
	while (j<n2) arr[k++] = R[j++]; 
}

void mergesort(int arr[],int left, int right){
	if(left<right){
		int middle=(left+ right)/2;
		mergesort(arr, left, middle);
		mergesort(arr, middle+1,right);
		merge(arr, left, middle, right);
	}
}

 int main() {
 	int n;
	scanf("%d",&n);
	for(int i=0;i<n;i++) scanf("%d", &A[i]);
	mergesort(A,0,n-1);
//	for(int i=0;i<n;i++) printf("%d ", A[i]);
	printf("%d", count);
}