#include <bits/stdc++.h>

using namespace std;

typedef long long ll;
#define fi first
#define se second
#define pb push_back
#define md ((st + nd) >> 1)
#define lc (1 + (idx << 1))
#define rc (2 + (idx << 1))
const int N = 100005;
char s[N];

int main() {
	scanf("%s", s);
	int n = strlen(s);
	int res = 1e9;
	for (char c = 'a'; c <= 'z'; c++) {
		int cost = 0;
		for (int i = 0; i < n; i++) {
			cost += abs(c - s[i]);
		}
		res = min(res, cost);
	}
	printf("%d", res);
	return 0;
}