stop_words = (" a ", " an ", " and ", " are ", " as ", " at ", " be ", " but ", " by ", " for ", " if ", " in ", " is ", " it ", " of ", " on ", " or ", " so ", " that ", " the ", " to ", " with ")
punctuation_marks = (".", ",", "?", "!", ":", ";", "'", "\"", "''", "(", ")", "[", "]", "{", "}", "-", "—", "...", "/", "\\", "&", "*", "@", "#", "_", "~", "|", "<", ">", "=", "+")

def removePunctuationMarks(text: str) -> str:
    for mark in punctuation_marks:
        text = text.replace(mark, '')
    return text

def removeStopWords(text: str) -> str:
    for word in stop_words:
        text = text.replace(word, ' ')
    return text

def main():
    print('welcome')
    sentence = input('enter a sentence:\n')
    sentence = ' ' + sentence
    sentence = removePunctuationMarks(sentence)
    sentence = removeStopWords(sentence)

    print('sentence with removed stuff is:\n', sentence)

if __name__== "__main__":
    main()