#include<iostream>
#include<cstdio>
#include<cstring>
#include<algorithm>
#include<iomanip>
#include<cmath>
#include<string>
#include<stack>
#include<queue>
#include<set>
using namespace std;
#define MAXN 500010
#define R(x) x=read()
#define W(x) write(x)
inline int read()
{
	int x,y;
	char c=getchar();
	x=0,y=1;
	while(c<'0'||c>'9') {if(c=='-') y=-1;c=getchar();}
	while(c>='0'&&c<='9') {x=(x<<3)+(x<<1)+(c^'0');c=getchar();}
	return x*y;
}
inline void write(int x)
{
	if(x<0) {putchar('-');x=-x;}
	if(x>9) write(x/10);
	putchar(x%10+'0');
}
struct node
{
	int value;
	int judge;
}a[MAXN];
int b[MAXN]
int lowbit(int);
void updata(int,int);
int getsum(int);
int c[MAXN]={0};
int n;
bool cmp(node a,node b)
{
	return a.judge>b.judge;
}
int main()
{
	R(n);
	for(int i=1;i<=n;i++) {R(a[i].judge);a[i].value=i;} 
	sort(a+1,a+1+n,cmp);
	long long sum=0;
	for(int i=1;i<=n;i++)
	{
		updata(a[i].value,1);
		sum+=getsum(a[i].value-1);
	}
	cout<<sum;
	return 0;
}
int lowbit(int x)
{
	return x&(-x);
}
void updata(int i,int v)
{
	while(i<=n)
	{
		c[i]+=v;
		i+=lowbit(i);
	}
}
long long getsum(int i)
{
	long long sum=0;
	while(i>0)
	{
		sum+=c[i];
		i-=lowbit(i);
	}
	return sum;
}