Lua code golf problem
I've been playing around with this code golf problem: 
https://www.spoj.pl/SHORTEN/problems/KAMIL/

I've got my solution down to 55 characters:

    for l in io.lines()do print(2^#l:gsub("[^TDLF]",""))end

Now, the shortest submitted solution in Lua is 47 characters long. I just 
can't figure out how to further reduce mine and it's been driving me crazy. 
Does anyone have a hint for me? I've tried working on io.read("*a") to get 
rid of the loop but it didn't help.
Lua code golf problem
===

I've been playing around with this code golf problem: 
https://www.spoj.pl/SHORTEN/problems/KAMIL/

I've got my solution down to 55 characters:

    for l in io.lines()do print(2^#l:gsub("[^TDLF]",""))end

Now, the shortest submitted solution in Lua is 47 characters long. I just 
can't figure out how to further reduce mine and it's been driving me crazy. 
Does anyone have a hint for me? I've tried working on io.read("*a") to get 
rid of the loop but it didn't help.