#include<stdio.h>
#define MAX 200000
#define SENTINEL 2000000000

int L[MAX/2+2],R[MAX/2+2];

long merge(int A[],int n,int left,int mid,int right){
   int i,j,k=0;
   long cnt=0;
  int n1;
  int n2;
  n1=mid-left;
  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]=SENTINEL;
  R[n2]=SENTINEL;
  i=0,j=0;
  for(k=left;k<right;k++){
      if(L[i]<=R[j]){
	A[k]=L[i];
	i++;
      }
      else{
	A[k]=R[j];
	j++;
	cnt+=n1-i;
      }
    }
  return cnt;
  }



long mergesort(int A[],int n,int left,int right){
  int mid;
  long v1,v2,v3;
  if(left+1<right){
   mid=(left+right)/2;
   v1=mergesort(A,n,left,mid);
   v2=mergesort(A,n,mid,right);
   v3=merge(A,n,left,mid,right);
   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,0,n);
  printf("%ld\n",ans);
  return 0;
}

