unique occurances

blah blah blah

for this problem, loop over every line in the input, count the number of unique letters in each line, and add those up

example

abcdab
aaaaaa
cdeeef

abcdab -> this line has 4 unique letters: abcd
aaaaaa -> this line has 1 unique letter: a
ccdeee -> this line has 3 unique letters: 3

4 + 1 + 3 = 8