1
2 2
1 1
1 2
 1
1 3
3
1 2 3
 1
1 1
1000
1000
 1
2 2
2 2
2 2
 5
4 5
10 8 6 4
1 2 3 4 5
1 1
3
3
1 1
3
2
5 3
1000 2 2 2 3
3 1 5
5 5
1 2 3 4 5
1 2 3 4 5
 1
4 4
1 1 1 1
1 2 3 4
 1
2 3
1 1
1 2 3

YES
1 1
 YES
1 3
 YES
1 1000
 YES
1 2
 YES
1 4
YES
1 3
NO
YES
1 3
YES
1 1
 YES
1 1
 YES
1 1

#include <bits/stdc++.h>
using namespace std;
int main() {
  int sum1 = 0, diff = 0, flag = 97;
  string a, b;
  cin >> a;
  for (int i = 0; i < a.size(); i++) {
    diff = abs(a[i] - flag);
    if (diff > 13) {
      diff = 26 - diff;
    }
    sum1 += diff;
    flag = a[i];
  }
  cout << sum1 << "\n";
}
