tall numbers

import java.util.*;

class Solution
{

    public static void main(String args[])
    {
        Scanner in = new Scanner(System.in);
        String n = in.nextLine();

        System.out.println(isTall(n)?true:false);
    }

    public static boolean isTall(String n)
    {
        for(int i = 1; i < n.length(); i++)
            if(n.charAt(i) < n.charAt(i-1))
                return false;
        return true;
    }
}