using namespace std;

const int MAX=100010;

long long a[MAX],temp[MAX];

int depart(int begin,int end)

{

int sum=0;

int mid=(begin+end)/2;

if(begin==end) return 0;

else

{

sum+=depart(begin,mid)+depart(mid+1,end);

int i=begin,j=mid+1,p=begin;

while(i<=mid && j<=end)

{

if(a[i]>a[j]) {temp[p++]=a[j++];sum+=mid-i+1;}

else temp[p++]=a[i++];

}

while(j<=end) temp[p++]=a[j++];

while(i<=mid) temp[p++]=a[i++];

for(int i=begin;i<=end;i++) a[i]=temp[i];

return sum;

}

}

int main()

{

int n;

cin>>n;

for(int i=0;i<n;i++) cin>>a[i];

cout<<depart(0,n-1);

}