#!/usr/bin/env lua
require("ext")
local items = {}
for start, finish in pairs({a = 'z', A = 'Z'}) do
	for k = start:byte(), finish:byte() do
		items[string.char(k)] = true
	end
end

local groups = {}
for line in io.lines() do
	local expanded = {}
	line:gsub("(%w)",function(w) expanded[w] = true end)
	table.insert(groups,expanded)
end
local common = {}
for i = 1,#groups,3 do
	for item, _ in pairs(items) do
		if groups[i][item] and groups[i + 1][item] and groups[i + 2][item] then
			table.insert(common, item)
			break
		end
	end
end
local sum = 0
for _, p in pairs(common) do
	if p >= 'a' and p <= 'z' then
		sum = sum + (p:byte() - ('a'):byte() + 1)
	elseif p >= 'A' and p <= 'Z' then
		sum = sum + (p:byte() - ('A'):byte() + 1) + 26
	end
end
print(sum)