import re
import string

word = " ident assignment ident operator number operator ident"


def boo(s):
    tokens = s.lstrip()  # removes the leading whitespaces

    statement1 = ["assign_stmt", "expression"]  # need space in front of all stuff
    assignment_stmt = ["ident assignment expression"]
    expression1 = ["ident", "number", "ident operator expression", "number operator expression"]

    if tokens == statement1:
        tokens = "statement"
    else:
        keep_going = True
        lst = tokens.split(" ")  # converts the string into a list
        while keep_going:
            keep_going = False
            for x in range(len(lst)):
                one = (lst[x:])  # this makes it forget the leftmost piece
                two = ' '.join(one)  # makes the list into a string.
                print(two)

                if two in statement1:
                    lst[x:] = ["statement"]
                    # del lst[-1]
                    keep_going = True
                elif two in assignment_stmt:
                    lst[x:] = ["assign_stmt"]
                    # del lst[-1]
                    keep_going = True
                elif two in expression1:
                    lst[x:] = ["expression"]
                    # del lst[-1]
                    keep_going = True


        final_lst = ' '.join(lst)
        print("here is final"+ final_lst)
        if final_lst == "statement":
            print ("Valid Statement")
        else:
            print ("Invalid Statement")






boo(word)