import javax.swing.plaf.basic.BasicInternalFrameTitlePane;
import java.math.BigInteger;
import java.util.Scanner;
public class Main{
static Scanner sc = new Scanner(System.in);
static int n=sc.nextInt();
static int[] q =new int[n+1];
static int[] temp =new int[n+1];
static long count=0;
public static void main(String[] args) {
for(int i=1;i<=n;i++)q[i]=sc.nextInt();
System.out.println(Merge(q,temp,1,n));
}
public static long Merge(int[] q, int[]temp,int l, int r){
if(l>=r)return 0;
int mid=(l+r)/2;
count=Merge(q,temp,l,mid)+Merge(q,temp,mid+1,r);
int k=1,i=l,j=mid+1;
while (i<=mid&&j<=r){
if(q[i]<=q[j])
temp[k++]=q[i++];
else {
temp[k++] = q[j++];
count+=mid-i+1;
}
}
while(i<=mid){
temp[k++]=q[i++];
}
while(j<=r)
temp[k++]=q[j++];
for( i=l,j=1;i<=r;i++,j++)q[i]=temp[j];
return count;
}
}