import math
import sequtils
import sets
import strutils

func priority(group: seq[string]): int =
  let sets = group.map_it it.to_hash_set
  var common = sets.foldl a * b
  result = common.pop.ord - 96
  if result < 0:
    result += 58

let
  elves = split_lines strip read_all stdin
  groups = elves.distribute elves.len div 3
echo sum groups.map priority