#!/usr/bin/env python

VALS = {}

for i in range(ord('a'), ord('z')+1):
    VALS[chr(i)] = i - ord('a') + 1

for i in range(ord('A'), ord('Z')+1):
    VALS[chr(i)] = i - ord('A') + 27

score = 0

with open('input') as f:
    for line in f:
        line = line.rstrip()
        half = len(line)//2
        compA = line[0:half]
        compB = line[half:len(line)]
        common = set(compA) & set(compB)

        score = score + VALS[common.pop()]

print(score)