#include <iostream>
#include <cmath>

using namespace std;

string s;
int ans = 2600000, x;

int main() {
// 	freopen("input.txt", "r", stdin);
// 	freopen("output.txt", "w", stdout);

	cin >> s;

	for (char i = 'a'; i <= 'z'; ++i) {
		x = 0;
		for (int j = 0; j < s.size(); ++j) {
			x += abs(i - s[j]);
		}

		ans = min(ans, x);
	}

	cout << ans << endl;
}