1 import java.util.Scanner;

 2

 3 public class Main {

 4     public static void main(String args[]){

 5              double sum=0;

 6              double bei=1;

 7              int len;

 8              int count=0;

 9         String str=null;

10         Scanner in=new Scanner(System.in);

11         str=in.next();

12         len=str.length();

13         if (str.charAt(0)=='-'){

14             len=str.length()-1;

15             bei=1.5;

16         }

17         for (int i=0;i<str.length();i++){

18             if (str.charAt(i)=='2'){

19                 count++;

20             }

21         }

22         int bei2=1;

23         if (Integer.parseInt(str.charAt(str.length()-1)+"")%2==0){

24             bei2=2;

25         }

26         sum=((double) count/len)*bei*bei2*100;

27         System.out.printf("%.2f%s",sum,"%");

28     }

29 }