#include <stdio.h>

#define MAX 200000
#define INFTY 2000000000

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

long long merge(int A[], int n, 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] = INFTY;
	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 n,int left,int right){
	int mid;
	long long 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]);
	}
	
	long long res = mergeSort(A,n,0,n);
	printf("%ld\n",res);

	return 0;

}
