#include<iostream>
using namespace std;
int main(){
	int i,a,b,c,x;
	i=3;
	x=0;
	while(i<=993){
		a=i/100;
		b=i/10%10;
		c=i%10;
		if(a==3||b==3||c==3){
			x=x+1;
			
		}
		
		i=i+1;
	}

	
	cout<<x<<endl;
	

}
		

/**************************************************************
	Problem: 1056
	User: admin
	Language: C++
	Result: Runtime Error
****************************************************************/