#include <stdio.h>

#define MAX 200000
#define SENTINAL 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] = SENTINAL;
	i =0;
	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 (void)
{
	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("%lld\n", ans);
	
	return 0;
}

