Problem: Grigoriy, like the hero of one famous comedy film, found a job as a night security guard at the museum. At first night he received embosser and was to take stock of the whole exposition.

Embosser is a special devise that allows to "print" the text of a plastic tape. Text is printed sequentially, character by character. The device consists of a wheel with a lowercase English letters written in a circle, static pointer to the current letter and a button that print the chosen letter. At one move it's allowed to rotate the alphabetic wheel one step clockwise or counterclockwise. Initially, static pointer points to letter 'a'. Other letters are located as shown on the picture:

<image>

After Grigoriy add new item to the base he has to print its name on the plastic tape and attach it to the corresponding exhibit. It's not required to return the wheel to its initial position with pointer on the letter 'a'.

Our hero is afraid that some exhibits may become alive and start to attack him, so he wants to print the names as fast as possible. Help him, for the given string find the minimum number of rotations of the wheel required to print it.

Input

The only line of input contains the name of some exhibit — the non-empty string consisting of no more than 100 characters. It's guaranteed that the string consists of only lowercase English letters.

Output

Print one integer — the minimum number of rotations of the wheel, required to print the name given in the input.

Examples

Input

zeus


Output

18


Input

map


Output

35


Input

ares


Output

34

Note

<image>

To print the string from the first sample it would be optimal to perform the following sequence of rotations: 

  1. from 'a' to 'z' (1 rotation counterclockwise), 
  2. from 'z' to 'e' (5 clockwise rotations), 
  3. from 'e' to 'u' (10 rotations counterclockwise), 
  4. from 'u' to 's' (2 counterclockwise rotations). 

In total, 1 + 5 + 10 + 2 = 18 rotations are required.

Solution (in PYTHON):

Solution:
__author__ = 'Devesh Bajpai'

'''
https://codeforces.com/problemset/problem/731/A

Solution: Iterate over the string and for every pair of adjacent characters, check if the forward or backward move
is optimal. For forward, we can take the difference of ascii values of previous and current character. Since we want
to know the moves, we take the difference as absolute. For the backward move, we subtract the forward move from 26, since
we have 26 characters only. Minimum of these moves is added to the total moves. 
In order to take care of the first character's move, we prepend 'a' to the string. 
'''


def solve(str):
    str = 'a' + str
    totalMoves = 0

    for i in xrange(1, len(str)):
        prevChar = str[i-1]
        curChar = str[i]

        forwardMove = abs(ord(prevChar) - ord(curChar))
        backwardMove = 26 - forwardMove

        totalMoves += min(forwardMove, backwardMove)

    return totalMoves



if __name__ == "__main__":
    str = raw_input()
    print solve(str)