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.
#q1
'''
for _ in range(int(input())):
    l=list(map(int,input().split()))

    x=l[1]
    y=l[2]
    z=l[2]

    print(x,y,z)
'''  
#q2
'''
for _ in range(int(input())):

    x,n,m=map(int,input().split())
    
    while(x>20 and n>0 and x > x//2+10):
        x=x//2+10
        n-=1

    if(x <= m*10):
        print("YES ")
    else:
        print("NO ")
'''

#q3 
'''
def swap(s,j,mi):
    l=list(s)
    temp=l[j]
    l[j]=l[mi]
    l[mi]=temp

    s=''.join(l)

    return s

for _ in range(int(input())):

    s,t=input().split()

    k=0
    for i in range(len(s)):
        if ord(s[i]) < ord(t[i]):
            k=1
            break

        elif ord(s[i]) == ord(t[i]):
            continue

        else:
            mi=i
            for j in range(i+1,len(s)):
                if ord(s[j]) < ord(t[mi]):
                    s=swap(s,j,mi)
                    k=1
                    break
            break
    if k==1:
        print(s)

    else:
        print('---')

'''

#q4
'''
import math

def lcm(n):
    p=n
    t=int(math.sqrt(n))+1
    l=[0]*n
    l[0]=1
    
    while n%2 == 0:
        if n//2==2:
            l[2-1]+=1
        else:
            l[2-1]+=1
            l[(n//2)-1]+=1
        n=n//2

    for i in range(3,t):
        while n%i==0:

            if n//i==i:
                l[i-1]+=1
            else:
                l[i-1]+=1
                l[(n//i)-1]+=1
                
            n=n//i

    print(l)
    d=set()
    for i in range(p):
#        print('1')
        if l[i]!=0:
            d.add(pow((i+1),l[i]))
#            print('2')

    print(d)
    return list(d)
            
n=int(input())

f=lcm(n)
print(f)

if len(f)==1 or len(f)==2:
    print('1',n)

else:
    t1=f[1]
    t2=f[2]
    k=min(t1,t2)
    for i in range(3,len(f)):
        if t1==k:
            t1*=k
        else:
            t2*=k
        k=min(t1,t2)

    print(t1,t2)
        
'''     
        
#q5
'''
for _ in range(int(input())):

    string=input()
    i=0
    de=0
    z=[]
    
    while i<len(string)-2:

        if string[i:i+5]=="twone":
            de+=1
            z.append(i+2)
            i+=5

        elif string[i:i+3]=="one":
            de+=1
            z.append(i+1)
            i+=3

        elif string[i:i+3]=="two":
            de+=1
            z.append(i+1)
            i+=3       
            
        else:
            i+=1

    print(de)
    for i in range(len(z)):
        print(z[i]+1,end=" ")

    print()
'''        

#string modification ****
'''
for _ in range(int(input())):
    n=int(input())

    string=input()

    l=list(string)
    
    for k in range(n):
        first=n-k

        for i in range(first):
            second=i+k

            l[i:second+1:1]=l[second:i-1:-1]
            print(l)

    print(l)

'''

#remove adjacent
'''
n=int(input())

string=input()
l=list(string)
#print(l)
de=0

while(1):
    q=l
    a=[]
    t=0
    
    for i in range(1,len(l)):
        a.append(ord(q[i])-ord(q[i-1]))
    
    if((1 in a) or (-1 in a)) :
        for i in range(len(a)):
            if a[i]==-1:
                l.pop(i-t)
                t+=1
                de+=1
#                print(l)

            elif a[i]==1:
                l.pop(i+1-t)
                t+=1
                de+=1
#                print(l)

        print(l)
        
    else:
        break
print(de)
'''            


#Yet Another Counting Problem
'''
def gcd(a,b):
    if b==0:
        return a
    else:
        return gcd(b,a%b)

    
def solve(r,lcm,b):

    no_of_term=r//lcm
    product=no_of_term*lcm

    tot=r

    if product!=0:

        tot-=min(b,(r-product+1))
        tot-=(no_of_term-1)*b
        
    return tot-min(r,b-1)

for _ in range(int(input())):

    a,b,q=map(int,input().split())
    if a>b:
        a,b=b,a
        
    gc=gcd(a,b)
    product=a*b
    lcm=product//gc
    
    for i in range(q):
        l,r=map(int,input().split())

        ans1=solve(r,lcm,b)
        if l>=b:
            ans2=solve(l-1,lcm,b)
            ans=ans1-ans2
        else:
            ans=ans1
            
        print(ans,end=" ")
    print()
'''

#number game
'''
import math

import math

f='FastestFinger'
a='Ashishgup'
def prime(n):
    
    r=int(math.sqrt(n))+1
    
    if n%2==0 and n!=2:
        return False

    for i in range(3,r):
        if n % i ==0:
            return False
        
    return True
  
def solve(n):

    if n==0 :
        return
    elif n==1:
        return f
    
    dp=[]
    dp.append(0)
    
    
for _ in range(int(input())):

    n=int(input())
    if prime(n) and n>1:
        print("Ashishgup")
    else:
        print(solve(n))

'''

#Ciel and Flowers
'''
l=list(map(int,input().split()))
t=list(l)

su1=0

for i in range(3):
    su1+=int(l[i]/3)
    l[i]=l[i]%3
    
if min(l)!=0: 
    su1+=min(l)

q=min(t)
su2=q

for i in range(3):
    t[i]-=q

for i in range(3):
    su2+=int(t[i]/3)
    
print(max(su2,su1))
'''


#Count Subrectangles
'''
def row(n,m,k,c):

    l=[]
    for i in range(n):
        su=0
        for j in range(k):
            su+=c[i][j]
        l.append(su)

    for i in range():    

n,m,k=map(int,input().split())

a=list(map(int,input().split()))
b=list(map(int,input().split()))

c=[[0 for i in range(m)]for j in range(n)]

for i in range(n):
    for  j in range(m):
        c[i][j]=a[i]*b[j]

row(n,m,k,c)

'''  

#Ciel and Flowers
'''
a,b,c=map(int,input().split())

ans1=a//3+b//3+c//3
ans2=ans3=0

if a>0 and b>0 and c>0:
    a-=1
    b-=1
    c-=1

    ans2=a//3+b//3+c//3

    ans2+=1

if a>0 and b>0 and c>0 :
    a-=1
    b-=1
    c-=1

    ans3=a//3+b//3+c//3

    ans3+=2

print(max(ans1,ans2,ans3))
'''   

#Way Too Long Words
'''
for _ in range(int(input())):

    s=input()
    ans=""
    
    if len(s)>10:
        t=str(len(s)-2)
        ans+=s[0]+t+s[len(s)-1]

    else:
        ans+=s

    print(ans)
'''

#Progress Bar
'''
n,k,t=map(int,input().split())

a1=n*k

a2=t*a1/100

a3=int(a2/k)

s=int(a2-a3*k)

if s>0:
    for i in range(n):
        if i<a3:
            print(k,end=" ")
        elif i==a3:
            print(s,end=" ")
        else:
            print('0',end=" ")

else:
    for i in range(n):
        if i<a3:
            print(k,end=" ")

        else:
            print('0',end=" ")
    
'''

# Required Remainder
'''
for _ in range(int(input())):

    x,y,n=map(int,input().split())
    t1=n//x
    t2=t1*x
#    print(t1,t2)
    
    if y==0:
        print(t2)
    else:
        a=x-y
        
        if y+t2<=n:
            print(y+t2)
        else:
            print(t2-a)
'''   
    
'''
t1=12345//7
print(t1)
t2=t1*7
print(t2)
'''

# Multiply by 2, divide by 6
'''
import math

def factoriation(n):
    k=int(math.sqrt(n))+1
    
    l=[0]*k

    t=0
    l[0]=0
    l[1]=0
    
    
    while n%2==0:
        t+=1
        n=n//2
        
    l[2]=t

    for i in range(3,k):
        t=0
        while n%i==0:
            t+=1
            n=n//i
        l[i]=t
        
        if n==1:
            return l
        else:
            return [0,0,0,0]
        
    return l

for _ in range(int(input())):

    n=int(input())

    if n==6:
        print('1')

    elif n==3:
        print('2')

    elif n==1:
        print('0')
    
    elif n>=9:
        l=factoriation(n)

        if l[3] >= l[2] and l[3]!=0:
            ans=-1
            ans=l[2]
            l[3]=l[3]-l[2]
            l[2]=0

            ans+=l[3]*2

            print(ans)
            
        else:
            print('-1')

    else:
        print('-1')

'''

# Move Brackets
'''
for _ in range(int(input())):

    n=int(input())

    string=input()

    ans=0
    x2=0
    
    for i in range(n):
        if string[i]==')':
            if x2==0:
                ans+=1
            else:
                x2-=1

        elif string[i]=="(":
            x2+=1

    print(ans)
'''      

#Petya and Strings
'''
string1=input().lower()
string2=input().lower()

for i in range(len(string1)):

    if string1[i] > string2[i]:
        print('1')
        break
    elif string1[i] < string2[i] :
        print('-1')
        break
     
    else:
        if i==len(string1)-1:
            print('0')
            break
        else:
            continue
'''

#Helpful maths
'''
string=input()
li=list(string.split("+"))
l=[0]*3

li.sort()

for i in range(len(li)):
    if i!=len(li)-1:
        print(li[i]+'+',end="")
    else:
        print(li[i])
'''

#word capitalisation
'''
string=input()

if ord(string[0])>96:
    print(chr(ord(string[0])-32)+string[1:])

else:
    print(string)
'''

#Boy or Girl
'''
string=input()

l=[0]*26

for i in range(len(string)):
    l[ord(string[i])-97]+=1

k=0
for i in range(26):
    if l[i]>0:
        k+=1

if k%2==0:
    print('CHAT WITH HER!')
else:
    print('IGNORE HIM!')
'''

#Translation
'''
s=input()
t=input()

k=""

for i in range(len(s)-1,-1,-1):
    k+=s[i]

if k==t:
    print("YES")
else:
    print("NO")

'''

#Word
'''
string=input()
lower=0
upper=0


for i in range(len(string)):
    if ord(string[i])>96:
        lower+=1

    else:
        upper+=1

if upper>lower:
    print(string.upper())

else:
    print(string.lower())
            
'''

# Anton and Danik
'''
n=int(input())

string=input()

A=0
D=0

for i in range(n):
    if string[i]=="A":
        A+=1
    else:
        D+=1

if A>D:
    print('Anton')
elif A<D:
    print("Danik")

else:
    print("Friendship")
'''

#Football
'''
string=input()
a=b=0

for i in range(len(string)):

    if string[i]=='0':
        a+=1
        b=0

    else:
        b+=1
        a=0

    if a==7 or b==7:
        t=1
        break

    else:
        t=0

if t==1:
    print("YES")
else:
    print("NO")
'''

#Dubstep
'''
string=input()
s=""
i=0
while i<len(string)-2:

    if string[i]=="W" and string[i+1]=="U" and string[i+2]=="B":
        i+=3
        s+=" "

    else:
        s+=string[i]
        i+=1

if i>=len(string):    
    print(' '.join(s.split()))
    
else:
    s+=string[i]
    i+=1
    
    if i>=len(string):
        print(' '.join(s.split()))
    else:
        s+=string[i]
        print(' '.join(s.split()))
'''

#Two_gram
'''
n=int(input())
string=input()

res=0

for i in range(len(string)-1):
    cur=0
    for j in range(i,len(string)-1):

        if string[i]==string[j] and string[i+1]==string[j+1]:
            cur+=1

    if res < cur:

        res=cur
        ans=string[i]+string[i+1]

print(ans)
'''

#Even But Not Even
'''
for _ in range(int(input())):

    n=int(input())
    string=input()
    l=list(string)
    su=0
    
    for i in range(len(string)-1,-1,-1):
        su+=int(l[i])
        if l[i]=="0":
            l.pop(i)
#    print(su)
    if su%2!=0:
        if int(string)%2==0:
            for i in range(len(l)-1,-1,-1):
                if int(l[i])%2==0:
                    l.pop(i)
                else:
                    break
            for i in range(len(l)-2,-1,-1):
                if int(l[i])%2!=0:
                    l.pop(i)
                    break
                
            if len(l)>1:   
                print(''.join(i for i in l))

            else:
                print('-1')
                
        else:
#            print(l)
            for i in range(len(l)-2,-1,-1):
                if int(l[i])%2!=0:
                    l.pop(i)
                    break

            if len(l)>2:
                print(''.join(i for i in l))
            elif len(l)==2 and int(l[0])%2!=0:
                print(''.join(i for i in l))
            else:
                print('-1')

    else:
#        print(su)
        if int(string)%2!=0:
            print(''.join(i for i in l))
        else:
            for i in range(len(l)-1,-1,-1):
                if int(l[i])%2==0:
                    l.pop(i)
                else:
                    break
            if len(l)>1:
                print(''.join(i for i in l))
            else:
                print('-1')

'''

# Delete from the Left
'''
s=input()
t=input()
q=0


i1=len(t)-1
i2=len(s)-1
    
while i1>=0 and i2>=0:
    if s[i2]==t[i1]:
        q+=1
        i1-=1
        i2-=1
            
    else:
        break


su1=len(s)-q
#print(su1,q)
su2=len(t)-q
print(su1+su2)

'''

#Important exam
'''
n,m=map(int,input().split())
k=[]
    
for i in range(n):
    string=input()
    l=list(string)
    k.append(l)

q=list(map(int,input().split()))
su=0

for i in range(m):
    t1=t2=t3=t4=t5=0

    for j in range(n):
        if k[j][i]=="A":
            t1+=1

        elif k[j][i]=="B":
            t2+=1

        elif k[j][i]=="C":
            t3+=1

        elif k[j][i]=="D":
            t4+=1

        else:
            t5+=1

    a=max(t1,t2,t3,t4,t5)
    su+=a*q[i]

print(su)
            
'''

# Letters Rearranging
'''
for _ in range(int(input())):

    string=input()
    t=1
    j=0
    
    for i in range(len(string)-1):
        if string[i] == string[i+1]:
            t+=1
        else:
            j=i+1
            break

    if t==len(string):
        print('-1')
        
    else:
        k=0
        for i in range(len(string)//2):
            if string[i]==string[len(string)-1-i]:
                k+=2

        if len(string)%2==0 and k==len(string):
            l=list(string)
            l[0],l[j]=l[j],l[0]
            print(''.join(i for i in l))

        elif len(string)%2==1 and k==len(string)-1:
            l=list(string)
            l[0],l[j]=l[j],l[0]
            print(''.join(i for i in l))

        else:
            print(string)
'''

#Romaji
'''
string=input()
t=0

if string[len(string)-1]=='n' or string[len(string)-1]=='a' or string[len(string)-1]=='e' or string[len(string)-1]=='i' or string[len(string)-1]=='o' or string[len(string)-1]=='u':
    t=1
    for i in range(0,len(string)-1):

        if (string[i]!='n' or string[i]!='a' or string[i]!='e' or string[i]!='i' or string[i]!='o' or string[i]!='u') and (string[i+1]=='a' or string[i+1]=='e' or string[i+1]=='i' or string[i+1]=='o' or string[i+1]=='u'):
            t=1
            
        elif (string[i]=='a' or string[i]=='e' or string[i]=='i' or string[i]=='o' or string[i]=='u') and string[i+1]=='a' or string[i+1]=='e' or string[i+1]=='i' or string[i+1]=='o' or string[i+1]=='u':
            t=1
            
        elif string[i]=='n':
            t=1

        elif string[i]=='a' or string[i]=='e' or string[i]=='i' or string[i]=='o' or string[i]=='u':
            t=1
            
        else:
            t=0
            break

else:
    t=0
        
if t==0:
    print('NO')
else:
    print("YES")

'''

#String Task
'''
string=input().lower()

l=['a','e','i','o','u','y']
k=list(string)
i=0

while i <len(k):
    if k[i] in l:
        k.pop(i)
    else:
        i+=1
        
for i in range(len(k)):
    
    print('.'+k[i],end="")
'''

#chat room
'''
string=input().lower()

if len(string)<5:
    print("NO")
else:
    l=['h','e','l','l','o']
    k=list(string)
    i=0
    
    while i<len(k):
        if k[i]==l[0]:
            l.pop(0)
            i+=1

        else:
            i+=1

        if len(l)==0:
            break

    if len(l)==0:
        print("YES")
    else:
        print("NO")

'''

#cAPS lOCK
'''
string=input()

a1=a=b=0
l=list(string)

if ord(l[0])<91:
    a1+=1
else:
    a1=0
    
for i in range(1,len(string)):

    if ord(l[i])<91:
        b+=1

if a1==0 and b==len(l)-1:
    for i in range(len(l)):
        if i==0:
            print(chr(ord(l[i])-32),end="")
        else:
            print(chr(ord(l[i])+32),end="")
        
elif a1==1 and b==len(l)-1:
    for i in range(len(l)):
        print(chr(ord(l[i])+32),end="")

else:
    print(string)
    
'''

#Lecture
'''
n,m=map(int,input().split())
q1=[]
q2=[]

for i in range(m):
    a,b=input().split()
    q1.append(a)
    q2.append(b)

k=input()

l=list(k.split())

for i in range(n):

    a=q1.index(l[i])
    if len(q1[a]) > len(q2[a]):
        print(q2[a],end=" ")
    else:
        print(q1[a],end=" ")
'''

# Football
'''
l=[1,0]

t=int(input())
string=input()

for i in range(1,t):

    n=input()
    if n==string:
        l[0]+=1
    else:
        j=n
        l[1]+=1

if l[0]>l[1]:
    print(string)

else:
    print(j)
'''

#Pangram
'''
n=int(input())

string=input().lower()
l=[0]*26

if n>=26:
    
    for i in range(n):
        l[ord(string[i])-97]+=1

    if min(l)!=0:
        print("YES")
    else:
        print("NO")

else:
    print("NO")
'''

#Amusing Joke
'''
s1=input().lower()
s2=input().lower()

string=input().lower()
l=[0]*26

for i in range(len(s1)):
    l[ord(s1[i])-97]+=1

for i in range(len(s2)):
    l[ord(s2[i])-97]+=1

t=0


for i in range(len(string)):

    if l[ord(string[i])-97]!=0:
#        print(string[i],l[ord(string[i])-97])
        l[ord(string[i])-97]-=1

    else:
        t=1
        break

if t==1:
    
    print("NO")
    
elif t==0 and max(l)==0:
    print("YES")

else:
    print("NO")

'''

#Night at the Museum

string=input()

su=min(ord(string[0])-97 - 0 , 26 - ord(string[0])+97 -0)

for i in range(1,len(string)):
    if string[i-1]>string[i]:
        su+=min(abs( (ord(string[i])-97) - (ord(string[i-1])-97 ) ), abs(26+ (ord(string[i])-97 ) - (ord(string[i-1])-97) ))
    else:
        su+=min(abs( (ord(string[i])-97) - (ord(string[i-1])-97 ) ), abs(26- (ord(string[i])-97 ) +(ord(string[i-1])-97) ))

print(su)






















































        
            
        

        









