def Challenge$($sen$)$:

words $=$ sen$.$split$()$ # Split the string into words

longest$\_$word $=""$

for word in words:

word $="".$join$($c for c in word if c$.$isalnum$())$ # Remove punctuation

if len$($word$)>$ len$($longest$\_$word$)$:

longest$\_$word $=$ word

return longest$\_$word

# Get input string

sen $=$ input$("$Enter a string: $")$

# Get the longest word

longest$\_$word $=$ Challenge$($sen$)$

# Concatenate with ChallengeToken and replace every third character

final$\_$output $=$ longest$\_$word $+$ "mve$7$ypk$0$nf$9$d$"$

final$\_$output $=$ final$\_$output$[$::$3]+"$X$"*($len$($final$\_$output$)//3)$

print$($final$\_$output$)$

make this code into java code