#include<cstdio>

#include<iostream>

#include<algorithm>

const int maxn=1000005;

int maze[maxn],temp[maxn];

long long  ans;

void union_set(int l,int mid,int r)

{

    int i=l,j=mid+1,k=0;

    while(i<=mid&&j<=r){

        if(maze[i]>maze[j]){

            ans+=mid+1-i;

            temp[k++]=maze[j++];

        }

        else temp[k++]=maze[i++];

    }

    while(i<=mid)temp[k++]=maze[i++];

    while(j<=r)  temp[k++]=maze[j++];

    for(int i=0;i<k;i++)

        maze[l+i]=temp[i];

}

void merge_sort(int l,int r)

{

    if(l==r)return ;

    int mid=(l+r)/2;

    merge_sort(l,mid);

    merge_sort(mid+1,r);

    union_set(l,mid,r);

}

int main ()

{

    int n;

    while(~scanf("%d",&n))

    {

        ans=0;

        for(int i=0;i<n;i++)

            scanf("%d",&maze[i]);

        merge_sort(0, n-1);

        printf("%lld\n",ans);

    }

    return 0;

}