#include <stdio.h>

long long Merge(int A[],int left,int mid,int right){
  int n1 = mid - left;
  int n2 = right - mid;
  int i,j,k;
  int L[n1+1],R[n2+1];
  long long res = 0;
  for (i = 0;i<n1;i++)L[i]=A[left+i];
  for (i = 0;i<n2;i++)R[i]=A[mid+i];
  L[n1]=1000000001;
  R[n2]=1000000001;

  i=j=0;
  for(k = left;k<right;k++)
    {
      if(L[i]<=R[j]){
        A[k]=L[i];
        i++;
        }
      else{
        A[k]=R[j];
        j++;
          res+=(long long)n1-(long long)i;
      }
    }
  return res;
}



long long Merge_Sort(int A[],int left,int right)
{
  int mid;
  long long res = 0;
  if(left + 1 < right){
    mid = (left + right)/2;

    res+=Merge_Sort(A,left,mid);
    res+=Merge_Sort(A,mid,right);
    res+=Merge(A,left,mid,right);
  }
  return res;
}
int  main(void)
{
  int i,n,S[200000];
  long long x;
  scanf("%d",&n);
  for (i = 0;i<n;i++)scanf("%d",&S[i]);
  x = Merge_Sort(S,0,n);
  printf("%ld\n",x);
  return 0;
}