#include<stdio.h>
#define MAX 200000
#define SENTINEL 2000000000
typedef long long ll;
int L[MAX / 2 + 2],R[MAX / 2 + 2];
ll merge(int A[], int n,int left,int mid, int right){
	int i,j,k;
	ll cnt = 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] = SENTINEL;
	i = j = 0;
	for(k = left;k < right; k++){
		if(L[i] <=R[j]){
			A[k] = L[i++];
		}
		else{
			A[k] = R[j++];
			cnt += n1 - i;
		}
	}
	return cnt;
}
ll mergeSort(int A[], int n,int left, int right){
	int mid;
	ll v1,v2,v3;
	if(left + 1<right){
		mid = (left + right) / 2;
		v1 = mergeSort(A,n,left,mid);
		v2 = mergeSort(A,n,mid,right);
		v3 = merge(A,n,left,mid,right);
		return v1+v2+v3;
	}
	else{
		return 0;
	}
}

int main (void){
	
	int A[MAX],n,i;
	scanf("%d",&n);
	for(i = 0;i < n;i++){
		scanf("%d",&A[i]);
	}
	ll ans = mergeSort(A,n,0,n);
	printf("%ld\n",ans);
	return 0;
}

