#include<stdio.h>
#define MAX 200000
#define S 1000000000
int L[MAX],R[MAX];
int  merge(int A[],int n,int left,int mid,int right){
  int i,j,k;
  int  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]=S;
  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 long mergeSort(int A[],int n,int left,int right){
  int mid;
  int 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;
  int ans;
  scanf("%d",&n);;
  for(i=0;i<n;i++)scanf("%d",&A[i]);
  ans=mergeSort(A,n,0,n);
  printf("%d\n",ans);
  return 0;
}