#include<stdio.h>
 
double count=0;
void margesort(int *,int,int);
void marge(int *,int,int,int);
 
int S[200000],L[100001],R[100001];
 
int main(){
  FILE* p;
  int n,i;
  //p=fopen("ALDS1_5_D_in19.txt","r");
  //fscanf(p,"%d",&n);
  scanf("%d",&n);
  for(i=0;i<n;i++) //fscanf(p,"%d",&S[i]);
     scanf("%d",&S[i]);
   
   margesort(S,0,n);
   printf("%.0f\n",count);
 
   //fclose(p);  
 
   return 0;
}
 
void margesort(int *S,int left,int right){
  int mid;
  if(left+1 < right){
    mid = (left + right)/2;
    margesort(S,left,mid);
    margesort(S,mid,right);
    marge(S,left,mid,right);
  }
}
 
void marge(int *S,int left,int mid,int right){
  int n1,n2;
  int i,j=0,k;
 
  n1 = mid - left;
  n2 = right - mid;
 
  for(i=0;i<n1;i++) L[i] = S[left+i];
  L[n1]=-1;
  for(i=0;i<n2;i++) R[i] = S[mid+i];
  R[n2]=-1;
 
  i=0;
  for(k=left;k<right;k++){
  if(L[i] > R[j]){ 
    S[k] = L[i];
    i++;
    count += n2 - j;
  }
  else{
    S[k] = R[j];
    j++;
  }
  }