#include<algorithm>
#include<bitset>
#include<iostream>
#include<iomanip>
#include<set>
#include<string>
#include<math.h>
#include<stack>
#include<string>
#include<queue>
#include<vector>
using namespace std;
typedef long long int ll;
typedef pair<int, ll> P;

//--------------
///#define DEBUG
//--------------

#ifdef DEBUG
	#define debugprint(x) cout<<x<<" "
	#define debugendl cout<<endl
	#define debug(x) x
#else
	#define debugprint(x)
	#define debugendl
	#define debug(x)
#endif

class zahyo{
	public:
	int x;
	int y;
	zahyo(){
		x=0;
		y=0;
	}
	zahyo(int x_,int y_){
		x=x_;
		y=y_;
	}
	void print(){
		cout<<x<<" "<<y;
	}
	zahyo operator+(zahyo add){
		add.x=this->x+add.x;
		add.y=this->y+add.y;
		return add;
	}
	zahyo operator-(zahyo add){
		add.x=this->x-add.x;
		add.y=this->y-add.y;
		return add;
	}
	zahyo operator*(int t){
		zahyo temp;
		temp.x=this->x*t;
		temp.y=this->y*t;
		return temp;
	}
	zahyo operator%(int t){
		zahyo temp(this->x%t,this->y%t);
		return temp;
	}
	zahyo operator/(int t){
		zahyo temp(this->x/t,this->y/t);
		return temp;
	}
	bool operator==(const zahyo add) const{
		if(add.x==this->x and add.y==this->y){return true;}
		else{return false;}
	}
	bool operator!=(const zahyo add) const{
		if(add.x==this->x or add.y==this->y){return false;}
		else{return true;}
	}
	bool operator<(const zahyo add) const{
		if(this->x<add.x){return true;}
		else if(this->x==add.x and this->y<add.y){return true;}
		else{return false;}
	}
	bool operator>(const zahyo add) const{
		if(this->x>add.x){return true;}
		else if(this->x==add.x and this->y>add.y){return true;}
		else{return false;}
	}
	void input(){
		cin>>x>>y;
	}
};

int main(){
	int n=0;
	cin>>n;
	//1+2
	int ans=0;
	int temp=0;
	for(int i=1;i<=9;i++){
			for(int j=0;j<=9;j++){
				temp=i*10+j;
				if(temp<=n and temp%3==0){
					ans++;
				}
			}
		}
	for(int i0=0;i0<4;i0++){
		for(int i1=0;i1<4;i1++){
			for(int i2=0;i2<4;i2++){
				for(int i3=0;i3<4;i3++){
					for(int i4=0;i4<4;i4++){
						for(int i5=0;i5<4;i5++){
							for(int i6=0;i6<4;i6++){
								for(int i7=0;i7<4;i7++){
									for(int i8=0;i8<4;i8++){
										temp=i0*pow(10,0)
											+i1*pow(10,1)
										+i2*pow(10,2)
										+i3*pow(10,3)
										+i4*pow(10,4)
										+i5*pow(10,5)
										+i6*pow(10,6)
										+i7*pow(10,7)
										+i8*pow(10,8);
										temp=temp*3;
										if(temp<=n and temp>100){
											ans++;
										}
									}
								}
							}
						}
					}
				}
			}
		}
	}
	cout<<ans<<endl;
}