#include <stdio.h>

#define MAX 200000
#define SENTINEL 2000000000
typedef long long llong;

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

llong merge(int A[], int n, int left, int mid, int right){
	int i, j, k;
	llong 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;
}

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

