Guess the word

import random

#---------------------------lists and variables-------------------
words=["apple","programming","christmas","Hangman"]
word=random.choice(words)
tries=0
guessed_letters=''
#---------------------------Functions-----------------------------
def check(guess):
    if guess.lower()==word.lower():
        print("Correct! It only took you %s tries." % tries)
    elif len(guess)==0 or len(guess)>=2:
        print("Invalid.This is not counted as a try.")
        main()
    elif len(guess)== len(word):
        print("Nice try, but that was not the word:")
        tries+=1
        main()
    elif guess.isalpha():
        global guessed_letters
        if guessed_letters.find(guess)>-1:
            print("You have already guessed that letter.")
            main()
        else:
            guessed_letters= guessed_letters+guess
            pass
    else:
        print("Invalid.This is not counted as a try.")
        main()
def board():
    for letter in word:
        if guessed_letters.find(letter)>-1:
            print(letter, end=" ")
        else:
            print("-",end=" ")
    print()


def main():
    global tries
    while True:
        if tries>=10:
            print("You got hung! The word was %s." % word)
            break
        board()
        print("Tries you took out of 10:%s" % tries)
        print("The word contains %s letters." % len(word))
        guess=input("Guess a letter or the word itself:")
        check(guess)
        tries+=1


main()