Python | Word Swap

So right now i'm still learning python, and I've been practicing 'regex' for the past hour, and used the tenacious d song list file as an example, here's the code

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import re def main(): fh = open ('rotf.txt') v = input('What word would you like to change? ') b = input('What word would you like to swap it with? ') for line in fh: match = re.search(v, line) if match: print(line.replace(match.group(), b), end='') main()

In the list there are songs consisting of the 'f' word (if you know what I mean) so i wanted to change the 'f' word, to 'caress', and this is what i got: 

Caress Her Gently

Hard Caressing

I Wanna Caress You

They Caressed Our Asses

(I found this very amusing)