#include <stdio.h>

#define N_MAX 200000
#define S_MAX 2000000000

long long int c;

void merge(int a[], int left, int mid, int right){
	int n1 = mid - left;
	int n2 = right - mid;
	int i, j, k;
	long long int L[n1+1],R[n2+1];
	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] = S_MAX;
	for(i = 0, j = 0, k = left ; k < right ; k++){
   		if(i < n1 && (j == n2 || L[i] <= R[j])){
      		a[k] = L[i++];
    	}
		else{
     		c += (n1 + n2) / 2 - i;
     		a[k] = R[j++];
    	}
  	}
}
 
void mergeSort(int a[], int left, int right){
  int mid;
  if(left + 1 < right){
    mid = (left + right) / 2;
    mergeSort(a, left, mid);
    mergeSort(a, mid, right);
    merge(a, left, mid, right);
  }
}
	
int main(void){
	int i;
	int A[N_MAX];
	long long int n;
	scanf("%d" ,&n);
	for(i = 0; i < n; i++){
		scanf("%d" ,&A[i]);
	}
	mergeSort(A,0,n); 
	printf("%lld\n",c);
	return 0;
}
