#include<cstdio>

#include<iostream>

using namespace std;

#include<algorithm>

#include<cstring>

#define MAXN 1000001

struct node {

    long long v;

    int id;

    bool operator<(const node &p) const{return v<p.v;}

};

node a[MAXN+];

long long int  c[MAXN+],b[MAXN+];

int n;

inline int lowbit(int x)

{

    return x&(-x);

}

long long query(int x)

{

    long long ans=;

    while(x)

    {

        ans+=c[x];

        x-=lowbit(x);

    }

    return ans;

}

void change(int x)

{

    while(x<=n)

    {

        c[x]++;

        x+=lowbit(x);

    }

}

int main()

{

    scanf("%d",&n);

    memset(a,,sizeof(a));

    memset(c,,sizeof(c));

    memset(b,,sizeof(b));

    for(int i=;i<=n;++i)

    {

        scanf("%d",&(a[i].v));

        a[i].id=i;

    }

    sort(a+,a+n+);

    int pre=-;

    int prevalue=;

    for(int i=;i<=n;++i)

    {

        if(pre!=a[i].v)

        {

            pre=a[i].v;

            a[i].v=++prevalue;

        }

        else a[i].v=prevalue;

    }

    for(int i=;i<=n;++i)

    b[a[i].id]=a[i].v;

    long long int s=;

    for(int i=n;i>=;--i)

    {

        change(b[i]);

        s+=query(b[i]-);

    }

    cout<<s<<endl;

    return ;

}