using System;

public class Program

{

    public static void Main (){

        //Code

    Program pp = new Program();

    int count2 = pp.count(99);

    Console.WriteLine(count2);

    }

    public int count(int number){

        int result = 0;

        for(int i = 0; i<=number; i++){

            result += has2(i);

        }

        return result;

    }

    public int has2(int n){

       int ct=0;

        while(n != 0){

            if(n%10 == 2 ){

                ct++;

            }

            n = n/10;

        }

        return ct;

    }

}