General :: Remove Words In A File Using Sed Or Any Other Command?

i want to remove words "Max" and "constrained" in a file given below:

Max 0.003745 constrained
Max 0.004549 constrained
Max 0.001689 constrained

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and further want to replace "Max" by line number so that i can plot the resulting file. i searched in forum, but couldn't do what i wanted to do. e.g. i used

1)grep command

grep -v "Max" inputfile >outputfile

deletes whole line,and hence whole text.

2) sed command

cat inputfile |sed 's/ .{1,12} //g' >outputfile

gives output

0.003745constrained
0.004549constrained
0.001689constrained

[code]....