#include <stdio.h>

#define MAX 200000
#define INFTY 2000000000

typedef long long llong;

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

llong merge(int A[],int n,int left,int mid,int right){
int n1,n2,i,j,k;
 llong c=0;
  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]=INFTY;
  R[n2]=INFTY;
  i=0;
  j=0;

  for(k=left;k<right;k++){
    if(L[i]<=R[j]){
      A[k]=L[i++];
    }
    else{
      A[k]=R[j++];
      c+=n1-i;
    }
  }
  return c;
}

llong mergeSort(int A[],int n,int left,int right){
int mid;
 llong 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;
  llong ans;
  scanf("%d",&n);
  for(i=0;i<n;i++){
    scanf("%d",&A[i]);
  }

  ans=mergeSort(A,n,0,n);
  printf("%lld\n",ans);
  
  return 0;
}

