#include <stdio.h>
#define MAX 200000
typedef long long l;

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

l merge(int A[], int n, int left, int mid, int right){
	int i, j, k;
	l 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] = 2000000000, R[n2] = 2000000000;
	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;
}


l mergesort(int A[], int n, int left, int right){
	int mid;
	l 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]);
	
	l ans = mergesort(A, n, 0, n);
	printf("%lld\n", ans);
	
	return 0;
}
