#include <bits/stdc++.h>
using namespace std;
#define modulo 998244353
#define mod(mod_x) ((((long long)mod_x+modulo))%modulo)
#define Inf 2000000005

int N;
int ans = 0;

void dfs(long long n){
	if(n>N)return;
	if(n>=10)ans++;
	
	for(int i=0;i<=9;i+=3){
		if(n*10+i==n)continue;
		dfs(n*10+i);
	}
}

int main(){
	
	cin>>N;
	
	dfs(0);
	
	vector<int> t = {12,15,18,42,45,48,72,75,78,21,24,27,51,54,57,81,84,87};
	for(int i=0;i<t.size();i++){
		if(t[i]<=N)ans++;
	}
	
	cout<<ans<<endl;
	
	return 0;
}