import java.io.*;
import java.util.*;
public class Prince
{
    public static void Strialpha() 
    {
        Scanner s=new Scanner(System.in);
        String sa = s.nextLine();
        char[] ar=sa.toCharArray();
        int res=0;
        for(int i=0;i<sa.length();i++)
        {
               if(ar[i]>=97 )
    {
        System.out.println("Invalid input");
        return;
       
    }
    else
    {
          res=res*26+(sa.charAt(i)-65)+1;
    }
        }
        System.out.println(col);
}
public static void main(String[] args)
{
    Strialpha();
}
}