#include<iostream>



using namespace std;

const int N=1e6+10;
typedef long long ll;

int q[N],tmp[N];
int n;

ll merge(int l,int r)
{
    if(l>=r)return 0;
    int mid=l+r>>1;
   ll res=merge(l,mid)+merge(mid+1,r);

    int k=0,i=l,j=mid+1;
    while(i<=mid&&j<=r)
    {
        if(q[i]<=q[j])tmp[k++]=q[i++];
        else{            
            tmp[k++]=q[j++];
            res+=mid-i+1;
        }


    }
    while(i<=mid)tmp[k++]=q[i++];
    while(j<=r)tmp[k++]=q[j++];

    for(i=l,j=0;i<=r;i++,j++)q[i]=tmp[j];
    return res;
}



int main()
{
    scanf("%d",&n);
    for(int i=0;i<n;i++)
    scanf("%d",&q[i]);
    printf("%lld",merge(0,n-1));
   //cout<<merge(0,n-1)<<endl; 

    return 0;
}