#!/usr/bin/env python3

lines = (x.strip() for x in open("input.txt"))
s = 0

for line in lines:
    a = set(line[:len(line)//2])
    b = set(line[len(line)//2:])
    i = a.intersection(b)
    o = ord(i.pop())
    s += o-0x60 if o > 0x60 else o-38

print(s)