#include <iostream>
#include <string>
using namespace std;

int
getPriority(char c)
{
	// [1;52]
	if ('a' <= c && c <= 'z') return c - 'a' + 1;
	if ('A' <= c && c <= 'Z') return c - 'A' + 27;
	throw "unexpected input";
}

int
main()
{
	long total = 0;
	for (string line; getline(cin, line); ) {
		bool inFirstHalf[52] = {0};
		if (line.length() % 2 != 0) throw "unexpected input";
		int found = -1;
		for (int i = 0; i < line.length(); i++) {
			int p = getPriority(line[i]);
			if (i < line.length() / 2) {
				inFirstHalf[p-1] = true;
			} else {
				if (inFirstHalf[p-1]) {
					found = p;
					break;
				}
			}
		}
		if (found == -1) throw "bad input";
		total += found;
	}
	cout << total << endl;
}