#the list of atoms
atom=["Hydrogen","Helium","lithium","beryllium","boron","carbon","nitrogen","oxygen","fluorine","neon","sodium","magnesium","aluminum","silicon","phosphorus","sulfur","chlorine","argon","potassium","calcium","scandium","titanium","vanadium","chromium","manganese","iron","cobalt","nickel","copper","zinc","gallium","germanium","arsenic","selenium","bromine","krypton","rubidium","strontium","yttrium","zirconium","niobium","molybdenum","technetium","ruthenium","rhodium","palladium","silver","cadmium","indium","tin","antimony","tellurium","iodine","xenon","cesium"]
#main program
choice=""
while choice !="x":
    print("*+*+*+*+*+*+*+*+*+*+*+*+*+*+*+*+*+*+*+*+*+*+*+*+*+*+*+*+*+*+*")
    print("      A T O M   F I N D E R     ")
    print("*+*+*+*+*+*+*+*+*+*+*+*+*+**+*+*+*+*+*+*+*+**+*+*+*+*+*+*+*+*")
    print("\n")
    print("A:Append an atom to the list")
    print("B:Remove an atom from the list")
    print("c: Sort the list")
    print("D: print the list")
    print("E:print the length of the list")
    print("F:Find an atom in the list")
    print("Exit the program")
    print("\n")
    choice=input("choose an option: ")
   
    if choice=="A":
        name=input("enter the name of an atom to add: ")
        atoms.append(name)
        print(name,"has been added to the list")
       
        if choice=="B":
            name=input("enter the name of an atom to remove from the list: ")
            atoms.remove(name)
            print(name,"has been removed from the list")
           
            if choice=="C":
                atoms.sort()
                print(atoms)
               
                if choice=="D":
                    print(atoms)
                   
                    if choice=="E":
                        print(len(atoms))
                   
                    if choice=="F":
                        def  linsearch():
                            name=input("enter s search term")
                            stop=len(atoms)
                            for i in range(stop):
                                if atoms[1]==name:print(name,"is in the list")
                            else:
                                print(name,"is in the list")