def theLoveLetterMystery(s):
    letters = "abcdefghijklmnopqrstuvwxyz"
    
    i = 0
    j = len(s) - 1
    
    change_count = 0
    
    while i < j:
        if s[i] == s[j]:
            i += 1
            j -= 1
        else:
            idx_i = letters.index(s[i])
            idx_j = letters.index(s[j])
            temp_count = abs(idx_j - idx_i)
            
            change_count += temp_count
            i += 1
            j -= 1
        
    return change_count