#include<stdio.h>
 
#define MAX 200000
#define SE 2000000000
 
int L[MAX/2+2],R[MAX/2+2];
long v1,v2,v3;
 
long merge(int *A,int n,int left,int right,int mid){
  int i,j,k=0;
  long cnt=0;
 
  int n1=mid-left;
  int n2=right-mid;
 
  for(i=0;i<n1;i++) L[i]=A[left+i];
  for(i=0;i<n2;i++) R[i]=A[mid+i];
  L[n1]=R[n2]=SE;
  i=j=0;
  for(k=left;k<right;k++){
    if(L[i]<=R[j]){
      A[k]=L[i++];
    }
    else{
      A[k]=R[j++];
      cnt+=n1-i;
    }
  }
  return cnt;
}
 
long mergeSort(int *A,int n,int right,int left){
  int mid;
  long v1,v2,v3; 
 
  if(left+1<right){
    mid=(left+right)/2;
    v1=mergeSort(A,n,mid,left);
    v2=mergeSort(A,n,right,mid);
    v3=merge(A,n,left,right,mid);
    return v1+v2+v3;
  }
  else return 0;
}
 
int main(){
  int A[MAX],n,i;
  long ans=0;
 
  scanf("%d",&n);
 
  for(i=0;i<n;i++){
    scanf("%d",&A[i]);
  }
 
 
  ans=mergeSort(A,n,n,0);
  printf("%ld\n",ans);
 
  return 0;
}

