using System;

public class Program

{

    public static void Main()

    {

        Console.WriteLine(isTheStringValid("C2+C15=C12+H12".ToLower()));

    }

    public static bool isTheStringValid(string s){

        bool error = true;

        for( int i =0; i < s.Length; i++ ){

            if( !(s[i] == 'c' ||  s[i] == '+' ||  s[i] == 'h' ||  s[i] == '=' || char.IsDigit(s[i]) ) ){

                return false;

            }

        }

        return error;

    }

}