خطا هنگام اجرای ماژول pytz

سلام .من عبارت pip install pytz رو وارد کردم ولی این چیزی بود که جواب داد :The term 'pip' is not recognized as the name of a cmdlet, function, script file, or operable program. Check the spelling of the 
name, or if a path was included, verify that the path is correct and try again. الان چی کار کنم؟