#include <bits/stdc++.h>
using namespace std;

int main(){

  int n;
  cin >> n;
  int lim = min(100,n);
  vector<int> d;
  int count =0;

  bool last=true;
  while(n>0){
    d.push_back(n%10);
    n /= 10;
    last &= d.back()%3==0;
  }

  //for(auto& i : d) cout << i << ' ' ; cout << endl;
  
  bool dig = false;
  for(auto it = d.rbegin(); it != d.rend(); ++it){
    count *=4;
    if(!dig)count += (*it)/3;
    else count +=3;
    if(dig && (*it)==0) dig = true;
    else if((*it)%3!=0) dig = true;
    else dig = false;
  }
  count -= 3;
    
  //cout << count << endl;

  for(int i=10; i<=lim; i++)
    if(i%3==0 && i%10%3 !=0) count ++;

  if(last) count ++;

  cout << count << endl;
  
}