#include<stdio.h>
#define N 200000
#define M 2000000000
#define O 0
#define I 1
#define W 2

typedef long long int llong;

int L[N/W+W],R[N/W+W];

llong merge(int*,int,int,int,int);
llong mergeSort(int*,int,int,int);

int main(){
  int A[N],n,i;
  llong a;

  scanf("%d",&n);
  for(i=O;i<n;i++){
    scanf("%d",&A[i]);
  }
  a=mergeSort(A,n,O,n);
  printf("%lld\n",a);
  return O;
}
llong merge(int A[],int n,int left,int mid,int right){
  int i,j,k;
  int n1,n2;
  llong c=O;
  n1=mid-left;
  n2=right-mid;
  for(i=O;i<n1;i++){
    L[i]=A[left+i];
  }
  for(i=O;i<n2;i++){
    R[i]=A[mid+i];
  }
  L[n1]=R[n2]=M;
  i=j=O;
  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+I<right){
    mid=(left+right)/W;
    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 O;
}

