#include<iostream>
#include<cstdio>
#include<algorithm>
#include<vector>
using namespace std;
typedef long long LL;
const int N=1e5+10;
int lowbit(int x);
void add(int a, int b);
int get_sum(int x);
int tfind(int l, int r, int x);

int n;
int a[N];
LL tr[N];
vector<int> alls;

signed main()
{
    cin>>n;

    alls.push_back(0);
    for(int i=1;i<=n;i++)
    {
        scanf("%d", &a[i]);
        alls.push_back(a[i]);
    }

    sort(alls.begin(), alls.end());
    alls.erase(unique(alls.begin(), alls.end()), alls.end());

    LL ans=0;
    for(int i=1;i<=n;i++)
    {
        int x=tfind(0, alls.size()-1, a[i]);
        ans+=get_sum(alls.size()-1)-get_sum(x);
        add(x, 1);
    }

    cout<<ans<<endl;
}

int tfind(int l, int r, int x)
{
    while(l<r)
    {
        int mid=l+r>>1;
        alls[mid]>=x?r=mid:l=mid+1;
    }

    return l;
}

void add(int a, int b)
{
    for(int i=a;i<=alls.size()-1;i+=lowbit(i)) tr[i]+=b;
}

int get_sum(int x)
{
    LL sum=0;
    for(int i=x;i;i-=lowbit(i)) sum+=tr[i];
    return sum;
}

int lowbit(int x)
{
    return x&-x;
}