Problem:
 Score : 200 points    Problem Statement  Takahashi loves palindromes. Non-palindromic strings are unacceptable to him. Each time he hugs a string, he can change one of its characters to any character of his choice.  Given is a string S . Find the minimum number of hugs needed to make S palindromic.      Constraints   S is a string consisting of lowercase English letters.  The length of S is between 1 and 100 (inclusive).         Input  Input is given from Standard Input in the following format:  S       Output  Print the minimum number of hugs needed to make S palindromic.        Sample Input 1 redcoder      Sample Output 1 1  For example, we can change the fourth character to o and get a palindrome redooder .       Sample Input 2 vvvvvv      Sample Output 2 0  We might need no hugs at all.       Sample Input 3 abcdabc      Sample Output 3 2

Solution (Python):
S=input()
if len(S)%2==0:
    S_mae=S[:len(S)//2]
    S_ushiro=S[len(S)//2:]
else:
    S_mae=S[:len(S)//2+1]
    S_ushiro=S[len(S)//2:]
ans=0
for i in range(len(S_mae)):
    if S_mae[-i-1]!=S_ushiro[i]:
        ans += 1
print(ans)

Solution (Python):
s=input()
n=len(s)
ans=0
for i in range(n//2):
  if s[i]!=s[-(i+1)]:
    ans+=1
print(ans)

Solution (Python):

S=input()
ans=0
for i in range(len(S)//2):
    if S[i]!=S[-i-1]:
        ans+=1
print(ans)

Solution (Python):
s = str(input())
n = len(s)
t = s[::-1]
ans = 0
for i in range(n//2):
    if s[i] != t[i]: ans += 1
print(ans)

Solution (Python):
s = list(input())
ans = 0
halfidx = int((len(s)/2))
ary  = s[0:halfidx]
rary = list(reversed(s))[0:halfidx]
for i in range(0,halfidx):
    if (ary[i] != rary[i]):
        ans = ans + 1
print(ans)

Solution (Python):
S = input()

SR = S[::-1]
ans = 0

for i in range(len(S)//2):
  if S[i] != SR[i]:
    ans +=1
  
print(ans)

Solution (Python):
s = input()
cnt = 0
for i in range(int(len(s)/2)):
    if( s[i] != s[-(i+1)]):
        cnt+=1
print(cnt)

Solution (Python):
s = input()

l = 0
r = len(s)-1

c = 0
while l <= r:
    if s[l] != s[r]:
        c += 1
    l += 1
    r -=1
print(c)

Solution (Python):
def main():
    s = input()
    t = s[::-1]
    ans = 0
    for i in range(len(s)):
        if s[i] != t[i]:
            ans += 1
    print(ans//2)


    
    
if __name__ == "__main__":
    main()

Solution (Python):
ess = input()
sse = ess[::-1]
hugs = 0
for i in range(0, len(ess)):
  if ess[i] != sse[i]: hugs += 1
    
print(int(hugs/2))

Solution (Python):
s=input()
count=0
l,r = 0,len(s)-1
while l<=r:
  if s[l] != s[r]: count += 1
  l += 1
  r -= 1
print(count)

Solution (Python):
S = input()
ans=0
for i in range(int(len(S)/2)):
  if S[i]!=S[len(S)-1-i]:
    ans+=1
print(ans)

Solution (Python):
X=input()
def split(w):
    return [all for all in w]
before=split(X[0:int(len(X)/2)])
after=split(X[int(len(X)/2):])
c=0
ans=0
reverse=-1
if len(X)%2==1:
    after=after[1:]
for i in after:
    if after[c]!=before[reverse]:
        ans+=1
    c+=1
    reverse-=1
print(ans)

Solution (Python):
import sys

def LS2(): return list(sys.stdin.readline().rstrip())  

S = LS2()
n = len(S)

ans = 0
for i in range(n//2):
    if S[i] != S[n-1-i]:
        ans += 1

print(ans)

Solution (Python):
import math
s=list(input())
N=len(s)
x=0
for i in range(0,N):
    if s[i]!=s[N-1-i]:
        x+=1
x=math.ceil(x/2)
print(x)

Solution (Python):
ans=0
s=input()
for i in range(0,len(s)//2):
  if s[i]!=s[len(s)-i-1]:
    ans+=1
print(ans)

Solution (Python):


s = input()
k = s[::-1]
n = 0

for i in range(len(s)):
    if s[i] != k[i]:
        n += 1
        

print(n // 2)

Solution (Python):
s = input()
news = "".join(list(reversed(s[len(s)//2:])))
cnt = 0
for i in range(len(news)):
    if s[i] != news[i]:
        cnt += 1

print(cnt)

Solution (Python):
s = list(input())
c = 0
x = s[::-1]
for i in range(len(s)):
    if s[i] != x[i]:
        x[i] = s[i]
        c += 1
        s[::-1] = x
print(c)

Solution (Python):
s = list(input())
c = 0
x = s[::-1]
for i in range(len(s)):
    if s[i] != s[::-1][i]:
        s[i] = s[::-1][i]
        c += 1
print(c)

Solution (Python):
s = list(input())
c = 0
for i in range(len(s)):
    if s[i] != s[::-1][i]:
        s[i] = s[::-1][i]
        c += 1
print(c)

Solution (Python):
S = input()
N = len(S)
count =0
for i in range(N//2):
    if S[i]!=S[N-1-i]:
        count +=1

print(count)

Solution (Python):
import math
S=list(input())
N=len(S)
a=0
for i in range(0,N):
    if S[i]!=S[N-1-i]:
        a+=1
a=math.ceil(a/2)
print(a)

Solution (Python):
S = input()
Count = 0
for T in range(0,len(S)//2):
    if S[T]!=S[-T-1]:
        Count += 1
print(Count)

Solution (Python):
import sys
sys.setrecursionlimit(4100000)
import math
INF = 10**9

def main():
    S = input()

    ans = 0
    for i in range(len(S)//2):
        if S[i] != S[-(i+1)]:
            ans += 1
    print(ans)


if __name__ == '__main__':
    main()

Solution (Python):

s = input()
a = s[:len(s)//2]
a = a[::-1]
if len(s) % 2 == 0:
    b = s[len(s) // 2:]
else:
    b = s[len(s) // 2 + 1:]

ans = 0
for (x, y) in zip(a, b):
    if x != y:
        ans += 1
print(ans)

Solution (Python):
s = input()
n = len(s) // 2
p = n
j = -1

for i in range(n):
    if s[i] == s[j]:
        p -= 1
    j -= 1

print(p)

Solution (Python):
S = input() 
N=len(S)
h=0
for i in range(0,N//2):
    if S[i]!=S[N-1-i]:
            h+=1
print(h)

Solution (Python):
s = input()
n = len(s)
ans = 0
for i in range(n):
  if s[i]!=s[n-1-i]:
    ans+=1
print(ans//2)

Solution (Python):
Ss = input().rstrip()

lenS = len(Ss)

ans = 0
for S, T in zip(Ss[:lenS//2], Ss[::-1]):
    ans += S != T

print(ans)

Solution (Python):
s = str(input())
count = 0
for i, j in zip(s, s[::-1]):
    if i != j:
        count += 1
    else:
        pass
print(count//2)

Solution (Python):
my_str = str(input())
new_str = my_str[::-1]
mylist = list(my_str)
newlist = list(new_str)
count = 0

for i in range(0,len(my_str)):
  if mylist[i] == newlist[i]:
    continue
  else:
    count += 1

new_count = -(-count//2)

print(new_count)

Solution (Python):
S = input()
ctr = 0
for i in range (len(S)//2):
    A,B = S[i], S[-1-i]
    if A != B:
        ctr += 1
print(ctr)

Solution (Python):
def main():
    S = input()
    n = len(S)
    ans = 0
    for i in range(n//2):
        if not S[i]==S[n-i-1]:
            ans += 1
    print(ans)

main()

Solution (Python):
S=input()
ans=0
for i in range(len(S)//2):
  if S[i]!=S[-(i+1)]:
    ans+=1
print(ans)

Solution (Python):
s = input()
ans = 0
for i in range(len(s)):
  if s[i] != s[-(i+1)]:
    ans += 1
print(ans // 2)

Solution (Python):
s = input()
l = len(s)

cnt = 0
for i in range(l//2):
    if s[i] != s[l-1-i]:
        cnt += 1
print(cnt)

Solution (Python):
s=input()
n=len(s)
c=0

if n%2==1:
    for i in range((n-1)//2):
        if s[i]!=s[-i-1]:
            c+=1
else:
    for i in range(n//2):
        if s[i]!=s[-i-1]:
            c+=1
print(c)

Solution (Python):
S = input()
S = list(S)
N = len(S)
count = 0

for i in range(N//2):
	if S[i] != S[(N-1)-i]:
		S[i] = S[(N-1)-i]
		count += 1

print(count)

Solution (Python):
s = input()
if len(s) == 1:
    print('0')
else:
    if len(s) % 2 == 0:
        sa = s[:len(s)//2]
        sb = s[len(s)//2:]
        sbr = sb[::-1]
    else:
        sa = s[:(len(s)-1)//2]
        sb = s[(len(s)-1)//2:]
        sbr = s[::-1]
    n = 0
    for i in range(len(sa)):
        if sa[i] != sbr[i]:
            n += 1
    print(n)

Solution (Python):
import sys
def input(): return sys.stdin.readline().strip()
def mapint(): return map(int, input().split())
sys.setrecursionlimit(10**9)

S = list(str(input()))
length = len(S)
cnt = 0
for a, b in zip(S, S[::-1]):
    if a!=b:
        cnt += 1
print(cnt//2)

Solution (Python):
s = input()
if len(s) == 1:
  print(0)
  exit()
  
ans = 0  
for i in range(len(s)//2):
  if s[i] != s[(-1)*(i+1)]:
    ans += 1
  else:
    pass
  
print(ans)

Solution (Python):
s=input()
t=0
for i in range((len(s))//2):
    if s[i]!=s[len(s)-i-1]:
        t+=1
print(t)

Solution (Python):
import copy
def solve():
    s = input()
    count = 0
    for i in range(len(s) // 2):
        if s[i] != s[-(i+1)]:
            count += 1
    print(count)




if __name__ == '__main__':
    solve()

Solution (Python):
S = list(input())
n = len(S)
ans = 0
for i in range(n//2) :
    if S[i] != S[n-1-i] :
        ans += 1

print(ans)

Solution (Python):
import sys
input = lambda: sys.stdin.readline().rstrip()

def main():
    s = list(input())
    ans = 0
    for i in range(len(s)//2):
        if s[i] != s[-(i+1)]:
            ans += 1
    print(ans)

if __name__ == '__main__':
    main()

Solution (Python):
s = input()
s_r = list(reversed(s))
s = s[:len(s)//2]
s_r = s_r[:len(s_r)//2]

count = 0
for i in range(len(s)):
    if s[i] != s_r[i]:
        count += 1

print(count)

Solution (Python):
S=input()
h=len(S)//2
l=S[0:h]
r=S[h:]
Rr=r[::-1]

ans=0

for i in range(h):
    if l[i]==Rr[i]:
        pass
    else:
        ans+=1
print(ans)

Solution (Python):
S = input()

ans = 0
n = len(S)


for i in range(n//2):
    if S[i] != S[-i-1]:
        ans += 1

print(ans)

Solution (Python):
s = input()
l = len(s)
if l % 2 == 0:
    s_a = s[:l // 2]
    s_b = ''.join(list(reversed(s[l // 2:])))
else:
    s_a = s[:l // 2]
    s_b = ''.join(list(reversed(s[l // 2 + 1:])))

count = 0
for i in range(len(s_a)):
    if s_a[i] != s_b[i]:
        count += 1
print(count)

Solution (Python):
S = input()
N = len(S)

cnt = 0
for i in range(N // 2):
    if S[i] != S[N - 1 - i]:
        cnt += 1
print(cnt)

Solution (Python):
s = input()
len_ = len(s)
half = len(s) // 2
ans = 0

if len_ % 2 == 0:
    front = s[:half]
    back = s[half:][-1::-1]
    for i in range(len(front)):
        if front[i] != back[i]:
            ans += 1
else:
    front = s[:half]
    back = s[half+1:][-1::-1]
    for i in range(len(front)):
        if front[i] != back[i]:
            ans += 1

print(ans)

Solution (Python):
import math

S = input()
ans = 0
l = int(math.floor(len(S)/2))
for i in range(l):
    if S[i] != S[len(S)-1-i]:
        ans += 1
print(ans)

Solution (Python):
import math

S = input()
ans = 0
l = int(math.floor(len(S)/2))
for i in range(l):
    if S[i] != S[len(S)-1-i]:
        ans += 1
print(ans)

Solution (Python):
n=input()
c=0
for i in range(len(n)//2):
    if(n[i]!=n[len(n)-1-i]):
        c+=1
print(c)

Solution (Python):
s = input()
n = len(s)//2
count = 0
f = s[:n]   
l = s[-n:]
l = l[::-1]
for i in range(n):
    if f[i] != l[i]:
        count+=1
print(count)

Solution (Python):
def main():
    s = input(); total = 0
    for i in range(len(s) // 2):
        if s[i] != s[-i - 1]:
            total += 1
    print(total)
main()

Solution (Python):
import math
from collections import defaultdict
ml=lambda:map(float,input().split())
ll=lambda:list(map(int,input().split()))
ii=lambda:int(input())
ip=lambda:list(input())

"""========main code==============="""

s=ip()
ans=0
for i in range(len(s)//2):
    if(s[i]!=s[len(s)-1-i]):
        ans+=1
print(ans)

Solution (Python):
s = input()

iters = len(s) // 2

count=0
for i in range(iters):
    if s[i] != s[-(i+1)]:
        count+=1


print(count)

Solution (Python):
s = input()
n = len(s)
c = 0
for i in range(n // 2):
    if s[i] != s[-i -1]:
        c = c + 1
print(c)

Solution (Python):
s=input()
c=0
for i in range(int(len(s)/2)):
  if s[i]!=s[-1-i]:
    c+=1
print(c)

Solution (Python):
s = input()
cnt = 0
n = len(s)//2
for i in range(n):
    if s[i] != s[-1-i]:
        cnt += 1

print(cnt)

Solution (Python):
s=input()
n=len(s)//2
cnt=0
for i in range(n):
    if s[i]!=s[len(s)-1-i]:
        cnt+=1
print(cnt)

Solution (Python):
import sys
import heapq
import math
import fractions
import bisect
import itertools
from collections import Counter
from collections import deque
from operator import itemgetter
def input(): return sys.stdin.readline().strip()
def mp(): return map(int,input().split())
def lmp(): return list(map(int,input().split()))

s=input()
n=len(s)
ans=0
for i in range(n//2):
    if s[i]!=s[-1-i]:
        ans+=1
print(ans)

Solution (Python):
S = input()

S_r = list(reversed(S))

hug = 0
for i in range(len(S) // 2):
    if S[i] != S_r[i]:
        hug = hug + 1

print(hug)

Solution (Python):
s = input()
sa = s[:len(s)//2]
if len(s)%2 == 0:
    sb = s[len(s)//2:]
if len(s)%2 == 1:
    sb = s[len(s)//2+1:]

sbr = sb[::-1]
cnt = 0
for i in range(len(sa)):
    if sa[i] != sbr[i]:
        cnt+=1

print(cnt)

Solution (Python):
S =input()
a =int(len(S)/ 2)

x =0





for i in range(a):
    
    if S[i] != S[-(i+1)]:
        x += 1

print(x)

Solution (Python):
s = input()
ans=0
for i in range(len(s)//2):
    if s[i]!=s[~i]:
        ans+=1
print(ans)

Solution (Python):
S = input()
S_rev = S[::-1]

cnt = 0
for i in range(len(S) // 2):
    if S[i] != S_rev[i]:
        cnt = cnt + 1
print(cnt)

Solution (Python):
s=input()
cnt=0
n=len(s)
for i in range(n//2):
    if s[i]!=s[n-i-1]:
        cnt+=1

print(cnt)

Solution (Python):
s = input()
a = s[::-1]
ans = 0

for i in range(len(s)):
    if s[i] != a[i]:
        ans +=1
print(ans//2)

Solution (Python):
S=list(input())
T=S.copy()
T.reverse()
count=0
for i in range(len(S)):
    if S[i]!=T[i]:count+=1
print(count//2)

Solution (Python):
S = input()
count = 0
val = 0

if len(S) % 2 == 0:
    val = len(S)/2
else:
    val = (len(S)-1)/2

for i in range(len(S)):
    if S[i] != S[-i-1]:
        count += 1
    if i+1 == val:
        break

print(count)

Solution (Python):
s = input()
a = ""
b = ""
if len(s)%2==0:
    a = s[:(len(s)//2)]
    b = s[(len(s)//2):][::-1]
else:
    a = s[:(len(s)//2)]
    b = s[(len(s)//2)+1:][::-1]
cnt = 0
for a_, b_ in zip(a,b):
    if not a_ == b_:
        cnt += 1
print(cnt)

Solution (Python):
x = input()
a = x[::-1]
b = 0
c = 0
d = int(len(x))
while b + 1 <= d:
  if x[b] == a[b]:
    c = c
    b = b + 1
  else:
    c = c + 1
    b = b + 1
c = int(c/2)
print(c)

Solution (Python):
s = input()
n = len(s)
ans = 0
for i in range(0,n//2):
  if s[i] != s[(-1)*(i+1)]:
    ans += 1
 
print(ans)

Solution (Python):
s = input()
t = s[::-1]

cnt = 0
for i, j in zip(s, t):
  if i != j:
    cnt += 1
    
print(cnt // 2)

Solution (Python):
S=input()
S_len=len(S)
count=0
for i in range(int(S_len/2)):
  if S[i]!=S[S_len-i-1]:
    count+=1
print(count)

Solution (Python):
s = input()
count = 0
for i in range(len(s)//2):
    if s[i] != s[len(s)-1-i]:
        count += 1
print(count)

Solution (Python):
s = input()
n = len(s)
ans = 0
for i in range(n):
    if(s[i] != s[n-i-1]):
        ans += 1
print(ans//2)

Solution (Python):
S = input()
L = len(S) // 2
LS = list(S)

cnt = 0

for i in range(L):
    j = (i * -1) -1
    if LS[i] != LS[j]:
        cnt += 1

print(cnt)

Solution (Python):
s=input()
cnt=0
for i in range(len(s)//2):
  if s[i]!=s[(i*(-1))-1]:
    cnt+=1
print(cnt)

Solution (Python):

"""
B - Palindrome-philia
https://atcoder.jp/contests/abc147/tasks/abc147_b

"""
import sys


def solve(S):
    l, r = 0, len(S) - 1
    ans = 0
    while l < r:
        ans += (S[l] != S[r])
        l += 1
        r -= 1
    return ans


def main(args):
    S = input()
    ans = solve(S)
    print(ans)


if __name__ == '__main__':
    main(sys.argv[1:])

Solution (Python):
S = input()

result = 0

for i in range(len(S) // 2):
  
  if S[i] != S[-(i + 1)]:
    result += 1
print(result)

Solution (Python):
s = input()
n = len(s)
cnt = 0

for i in range(n//2):
    if s[i] != s[n-i-1]:
        cnt += 1
        
print(cnt)

Solution (Python):
N = input()
n = len(N) // 2
x = N[:n]
y = ''.join(list(reversed(N[-n:])))

count = 0
for i in range(n):
    if x[i] == y[i]:
        continue
    else:
        count += 1

print(count)

Solution (Python):
s = input()

ans = 0
for i in range(len(s) // 2):
    if s[i] != s[len(s) - i - 1]: ans += 1

print(ans)

Solution (Python):
s=input()
ans=0
for i in range(len(s)//2):
    if s[i]!=s[-(i+1)]:ans+=1
print(ans)

Solution (Python):
s=input();print(sum(a>b for a,b in zip(s,s[::-1])))

Solution (Python):
N = input()
A = N[::-1]


cont = 0
for i in range(len(N)):
	if N[i] > A[i]:
		cont+=1
print(cont)

Solution (Python):
s=input()

l=[]

for i in s:
  l.append(i)
new_l = l[::-1]

count=0
for a,b in zip(l,new_l):
  if a != b:
    count+=1
print(count//2)

Solution (Python):
def actual(s):
    N = len(s)
    count_operation = 0

    for i in range(N):
        head = s[i]
        tail = s[N - 1 - i]

        if head != tail:
            count_operation += 1

    return int(count_operation / 2)

s = input()
print(actual(s))

Solution (Python):
import numpy as np
import scipy as sp
import math

S = input()
n = len(S)
m = n//2
l = 0
for i in range (0,m):
  if(S[i] != S[n-i-1]):
      l = l + 1
print(l)

Solution (Python):
def main():
    S = list(input())

    cnt = 0


    for i in range(int(len(S) / 2)):
        if S[i] != S[-i - 1]:
            cnt += 1

    print(cnt)


if __name__ == "__main__":
    main()

Solution (Python):
s=input()
s1=s[:len(s)//2]
s2=s[len(s)//2:][::-1]
ans=0
for i in range(len(s)//2):
    if s1[i]!=s2[i]:
        ans+=1
print(ans)

Solution (Python):
S = input()

leng = len(S)
count = 0
if leng % 2 == 0:
  S1 = S[:int(leng/2)]
  S2 = S[int(leng/2):]
  for i in range(int(leng/2)):
    if S1[i] == S2[int(leng/2)-1-i]:
      count += 1
  print(int(leng/2)-count)
else:
  S1 = S[:int(leng/2)]
  S2 = S[int(leng/2)+1:]
  for i in range(int(leng/2)):
    if S1[i] == S2[int(leng/2)-1-i]:
      count += 1
  print(int(leng/2)-count)

Solution (Python):
s = input()
c = 0
for i in range(len(s)//2):
    if s[i] != s[-1-i]:
        c += 1
print(c)

Solution (Python):
S = input()
ans = 0
for i in range(len(S)//2):
    if S[i] != S[-i - 1]:
        ans += 1

print(ans)

Solution (Python):
def resolve():
    S = input()
    s = len(S)
    count = 0
    if s%2 == 0:
        for i in range(s//2):
            if S[i] != S[(i+1)*-1]:
                count += 1
    else:
        for i in range((s-1)//2):
            if S[i] != S[(i+1)*-1]:
                count += 1
    print(count)
resolve()

Solution (Python):
def resolve():
    S = input()
    s = len(S)
    count = 0
    if s%2 == 0:
        for i in range(s//2):
            if S[i] != S[(i+1)*-1]:
                count += 1
    else:
        for i in range((s-1)//2):
            if S[i] != S[(i+1)*-1]:
                count += 1
    print(count)
resolve()

Solution (Python):
s = input()
k = 0
for i in range(len(s) // 2):
  if s[i] == s[len(s) - i -1]:
    next
  else:
    k += 1
print(k)

Solution (Python):
import sys
import  math
import fractions
from collections import defaultdict
stdin = sys.stdin
     
ns = lambda: stdin.readline().rstrip()
ni = lambda: int(stdin.readline().rstrip())
nm = lambda: map(int, stdin.readline().split())
nl = lambda: list(map(int, stdin.readline().split()))

S=list(ns())

ans=0
for i in range(len(S)//2):
    if(S[i]!=S[-i-1]):
        ans+=1

print(ans)

Solution (Python):
s=input()
l=len(s)
c=0
for i in range(int(l/2)):
  if s[i]!=s[l-i-1]:
    c+=1
print(c)

Solution (Python):
s=input()
n=len(s)
if n%2==0:
  t=list(s[:n//2])
  u=list(s[n//2:])
  t.reverse()
  cnt=0
  for i in range(len(t)):
    if t[i]==u[i]:
      continue
      
    else:
      cnt+=1
  
else:
  t=list(s[:n//2])
  u=list(s[n//2+1:])
  t.reverse()
  cnt=0
  for i in range(len(t)):
    if t[i]==u[i]:
      continue
      
    else:
      cnt+=1
      
      
print(cnt)

Solution (Python):
s = input()

n = len(s)
cnt = 0
for i in range(n//2):
    if s[i] != s[n-i-1]:
        cnt += 1
print(cnt)

Solution (Python):
def palindrome(s):

    ans = 0

    for i in range(len(s)//2):
        if s[i] != s[-i-1]:
            ans += 1
    return ans

def main():
    s = list(str(input()))
    print(palindrome(s))

if __name__ == '__main__':
    main()

Solution (Python):
S = input()

Sr = S[ : : -1]

hug = 0
for i in range(len(S)):
    if S[i] != Sr[i]:
        hug += 1

print((hug + 1) // 2)

Solution (Python):

def main1():
    s = input()
    s1 = s[0:len(s)//2]
    s2 = s[::-1]
    s2 = s2[0:len(s)//2]
    ans = 0

    for i  in range(len(s)//2):
        if s1[i]==s2[i]:
            continue
        else:
            ans+=1
    print(ans)



if __name__ == '__main__':
    main1()

Solution (Python):
s = input()
cnt = 0
for i in range(int(len(s) // 2)):
  if s[i] != s[-i-1]:
    cnt += 1
print(cnt)

Solution (Python):
s = input()
s = list(s)
count = 0

for i in range(int(len(s)/2)):
  if s[i] == s[-(i+1)]:
    continue
  else:
    count += 1
    
print(count)

Solution (Python):
S = input()

count = 0
for i in range(len(S)//2):
    if S[i] != S[-(i+1)]:
        count += 1

print(count)

Solution (Python):
s=input()
n=len(s)
ans=0
for i,j in zip(s[:n//2],s[:n//2-1:-1]):
  if i!=j:
    ans+=1
print(ans)

Solution (Python):
s = input()
t = list(reversed(s))
ans = 0
for i in range(len(s)):
    if s[i] != t[i]:
        ans += 1
ans = (ans+1) // 2
print(ans)

Solution (Python):
import sys
import decimal 

def input():
    return sys.stdin.readline().strip()

def main():
    s = input()
    r = s[::-1]
    l = len(s)
    count = 0
    if l % 2 == 0:
        for i in range(l//2):
            if s[i] != r[i]:
                count += 1
        print(count)
        return
    for i in range(l//2 + 1):
        if s[i] != r[i]:
            count += 1
    print(count)
    

main()

Solution (Python):
S = input()
rS = reversed(S)

print(sum([s != rs for s, rs in zip(S, rS)]) // 2)

Solution (Python):
s=input()
l=len(s)
l2=l//2
count=0
for i in range(l2):
  if s[i]!=s[l-1-i]:
    count+=1
print(count)

Solution (Python):
def solve(x):
  if len(x) <= 1:
    return 0
  else:
    return (1 if x[0] != x[-1] else 0) + solve(x[1:-1])

s = input()
print(solve(s))

Solution (Python):
import sys
from collections import defaultdict
readline = sys.stdin.buffer.readline



def geta(fn=lambda s: s.decode()):
    return map(fn, readline().split())


def gete(fn=lambda s: s.decode()):
    return fn(readline().rstrip())


def main():
    s = gete()

    ans = 0
    for i in range(len(s) // 2):
        if s[i] != s[-1 - i]:
            ans += 1

    print(ans)


if __name__ == "__main__":
    main()

Solution (Python):
S=input()
ans=0
for i in range(len(S)//2):
    if S[i]!=S[len(S)-i-1]:
        ans=ans+1
print(ans)

Solution (Python):

s = input()
a = 0
for i in range(len(s)//2):
    a += s[i] != s[-i-1]
print(a)

Solution (Python):
s = input()
n = len(s)
t = 0

for i in range(int(n/2)):
    if s[i] != s[n-1-i]:
        t += 1

print(t)

Solution (Python):
s = input()
count = 0
for i in range(len(s)//2):
    if s[i] != s[-1-i]:
        count += 1
print(count)

Solution (Python):
s=input()
x=len(s)
ans=0
for i in range(int(x/2)):
    if s[i]!=s[x-1-i]:
        ans+=1
print(ans)

Solution (Python):
s = input()
x = len(s)
ans = 0
for i in range(int(x/2)):
  if s[i] != s[x-1-i]:
    ans += 1
print(ans)

Solution (Python):
S=input()
count=0
for i in range(len(S)//2):
  if S[i]!=S[-i-1]:
    count+=1
print(count)

Solution (Python):
s = input()
n = len(s)

ans = 0
for i in range(n//2):
  if s[i] != s[n-i-1]:
    ans += 1
    
print(ans)

Solution (Python):
s = input()
hug = 0
for i in range(len(s) // 2):
    if s[i] != s[len(s) - i - 1]:
        hug += 1
print(hug)

Solution (Python):
def func(S):
    T = S[::-1]
    ans = sum(1 for s, t in zip (S, T) if s != t) // 2
    return ans


if __name__ == "__main__":
    S = input()
    print(func(S))

Solution (Python):
s = input()
l = len(s)
ans = 0

for i in range(l // 2):
    if s[i]!=s[l-1-i]:
        ans += 1

print(ans)

Solution (Python):
s = input()
l = len(s)
half = l//2
check = 0
for i in range(half):
    if s[i] != s[l-1-i]:
        check += 1
print(check)

Solution (Python):
S = input().rstrip()
ans = 0
for i in range(len(S)//2):
    if S[i] != S[-i-1]:ans+=1
print(ans)

Solution (Python):
n=input()
ans=0
for i in range(len(n)//2):
    if not n[i]==n[-(i+1)]:
        ans+=1
print(ans)

Solution (Python):
s = input()

ans = 0

for i in range(len(s)//2):
    if s[i] != s[-i-1]:
        ans += 1

print(ans)

Solution (Python):
s = input()
n = len(s)

cnt = 0
for i in range(n//2):
  if (s[i] != s[n - 1 - i]):
    cnt+=1

print(cnt)

Solution (Python):
S = input()

ans = 0
for i in range(len(S)//2):
    if S[i ] == S[- i -1]:
        pass
    else:
        ans += 1

print(ans)

Solution (Python):
s = input()

rs = s[::-1]

cnt = 0
for i in range(len(s)):
    if s[i] != rs[i]:
        cnt += 1

print(int(cnt/2))

Solution (Python):
s = input()
count = 0
for i in range(len(s)):
  if len(s) % 2 == 0:
    limit = len(s) / 2
  else:
    limit = len(s) // 2 + 1
  
  if i >= limit:
    break
  
  if s[i] != s[-i-1]:
    count += 1
  

print(count)

Solution (Python):
s = input().rstrip()

si = 0
ei = len(s) - 1
num = 0
while si < ei:
    if s[si] != s[ei]:
        num += 1
    
    si += 1
    ei -= 1

print(num)

Solution (Python):
S = input()
count = 0
for i in range(len(S)//2):
    if S[i] != S[-i-1]:
        count = count + 1
        
print(count)

Solution (Python):

from collections import deque
s = deque(list(input()))
cnt = 0
while 1 < len(s):
    r = s.pop()
    l = s.popleft()
    if r != l:
        cnt += 1
print(cnt)

Solution (Python):
R=0
S=list(input())
c=len(S)
for i in range(c//2+1):
  if S[i]!=S[c-i-1]:
    R=R+1
    S[c-i-1]=S[i]
print(R)

Solution (Python):
s = input()
a = len(s)//2
count = 0
for i in range(a):
    if s[i] != s[len(s)-1-i]:
        count += 1
print(count)

Solution (Python):

import sys

read = sys.stdin.buffer.read
readline = sys.stdin.buffer.readline
readlines = sys.stdin.buffer.readlines


def main():
    S = readline().rstrip().decode()
    S_f = S[:len(S)//2]
    S_s = S[-len(S)//2:][::-1]
    ans = 0
    for s1, s2 in zip(S_f, S_s):
        if s1 != s2:
            ans += 1
    print(ans)


if __name__ == '__main__':
    main()

Solution (Python):
S = input()
count = 0
for i in range(len(S)//2):
  if S[i] != S[-i-1]:
    count+=1
print(count)

Solution (Python):
def main():
    s = input()
    t = s[::-1]
    count = 0
    for i in zip(s, t):
        if i[0] != i[1]:
            count += 1
    print(count // 2)

if __name__ == '__main__':
    main()

Solution (Python):
S = input()

ans = 0
lenS = int(len(S)/2)

for o,r in zip(S[:lenS], S[:lenS-1:-1]):
    if o != r:
        ans += 1
    
print(ans)

Solution (Python):
s = input()
ans = 0
for i in range(len(s)//2):
    if s[i] != s[-1-i]:
        ans += 1
print(ans)

Solution (Python):
S=input()
cnt=0
for i in range(len(S)//2):
  if S[i]!=S[-i-1]:
    cnt+=1
print(cnt)

Solution (Python):
s = input()
lst = list(s)
cnt = 0
for i in range(len(lst)):
    if lst[i] != lst[len(lst)-1-i]:
        lst[i] = lst[len(lst)-1-i]
        cnt+=1
print(cnt)

Solution (Python):
a=input()
b=a[::-1]
n=0
for i in range(len(a)//2):
  if a[i]!=b[i]:
    n+=1
print(n)

Solution (Python):
s = str(input())

rslt = s[::-1]

count = 0

if len(s)%2==0:

    for i in range(len(s)//2):

        if s[i] != rslt[i]:
            count += 1
else:
     for i in range(len(s)//2):

        if s[i] != rslt[i]:
            count += 1

           



print(count)

Solution (Python):
import sys

input = lambda: sys.stdin.readline().rstrip()


def solve():
    S = input()

    l = len(S) // 2
    l2 = len(S)
    ans = 0

    for i in range(l):
        if not S[i] == S[l2 - i - 1]:
            ans += 1

    print(ans)


if __name__ == '__main__':

    solve()

Solution (Python):
import math
s = input()

n = len(s)
m = math.ceil((n/2))

count= 0

for i in range(m):
    if s[i]!= s[-1-i]:
        count += 1
    else:
        pass

print(count)

Solution (Python):
import collections
s = raw_input()
count, i,j = 0,0, len(s) -1

while(i<j):
	if s[i]!= s[j]:
		count +=1
	i+=1
	j-=1
print count

Solution (Python):
import math
s = input()
S = s[::-1]
count = 0
for i in range(0, len(s)):
  if s[i] != S[i]:
    count += 1
print(math.floor(count/2))

Solution (Python):


def main():
    S = input()
    ans = 0
    for i in range(len(S) // 2):
        if S[i] != S[::-1][i]:
            ans += 1
    print(ans)

if __name__ == '__main__':
    main()

Solution (Python):


def main():
    S = input()
    ans = 0
    for i in range(len(S) // 2):
        if S[i] != S[len(S)-1-i]:
            ans += 1
    print(ans)

if __name__ == '__main__':
    main()

Solution (Python):
S = input()
count = 0
for i in range(len(S)//2):
    if S[i] != S[-(i+1)]:
        count += 1
print(count)

Solution (Python):
from sys import stdin, setrecursionlimit


def main():
    input = stdin.buffer.readline
    s = list(input()[:-1].decode())
    n = len(s)

    ans = 0
    for i in range(n // 2):
        if s[i] != s[n - i - 1]:
            ans += 1

    print(ans)


if __name__ == "__main__":
    setrecursionlimit(10000)
    main()

Solution (Python):
s = input()
r = s[::-1]
count = 0

for i in range(int(len(s))):
    if (s[i] != r[i]):
        count += 1

print(count//2)

Solution (Python):
import math
s = input()
a = 0
for i in range(math.ceil(len(s)/2)):
  if s[i] != s[-(i+1)]:
    a += 1
print(a)

Solution (Python):
S = list(input())

firstS = S[:len(S) // 2]
if len(S) % 2 == 0:
    secondS = list(reversed(S[len(S) // 2:]))
else:
    secondS = list(reversed(S[len(S) // 2 + 1:]))

count = 0

for x in range(len(firstS)):
    if firstS[x] != secondS[x]:
        count += 1
print(count)

Solution (Python):
s = str(input())
c = 0

for w in range(int(len(s)/2)):
    if s[w] != s[len(s)-1-w]:
        c+=1

print(c)

Solution (Python):
s = input()
r = s[::-1]
count = 0

for i in range(int(len(s))):
    if (s[i] != r[i]):
        count += 1

print(count//2)

Solution (Python):
S=input()
ans=0
for i in range(len(S)//2):
    if S[i]!=S[len(S)-1-i]:
        ans+=1
print(ans)

Solution (Python):
S = input()
cnt = 0
for i in range(len(S)//2):
    if S[i] != S[-(i+1)]:
       cnt +=1

print(cnt)

Solution (Python):
s = input()
count = 0
for i in range(len(s)//2):
  if s[i] != s[-(i+1)]:
    count += 1
print(count)

Solution (Python):
s=input()
n=len(s)
 
c=0
i=0
while i<n-i-1:
  if s[i]!=s[n-i-1]:
    c+=1
  i+=1
print(c)

Solution (Python):
s = input()
t = s[::-1]
ans = 0
for i in range(len(s)//2):
    if s[i] != t[i]:
        ans += 1
print(ans)

Solution (Python):
s = str(input())
count = 0

for i in range(len(s)//2):
    if s[i] != s[len(s)-i-1]:
        count += 1

print(count)

Solution (Python):
s = input()
f = 0
b = -1
c = 0

while f < len(s)//2:
    if s[f] != s[b]:
        c += 1
    f += 1
    b -= 1

print(c)

Solution (Python):
s = input()
l = len(s)

ans = 0

for i in range(l):
    if s[i] != s[-(i + 1)]:
        ans += 1
        
print(ans // 2)

Solution (Python):
s = input()
l = len(s)

if len(s) % 2 == 0:
    a = s[:l // 2]
    b = s[-l // 2:][::-1]
else:
    a = s[:l // 2]
    b = s[-(l // 2):][::-1]

ans = 0

for i in range(l//2):
    if a[i] != b[i]:
        ans += 1
        
print(ans)

Solution (Python):
S = input()
count = 0
for i in range((len(S)+1)//2):
    if S[i] != S[-i-1]:
        count += 1
print(count)

Solution (Python):
s = input()
leng = len(s)
count = 0
if leng %2!=0:
    for i in range(int((leng-1)/2)):
        if s[i] != s[leng-i-1]:
            count += 1
else:
    for i in range(int(leng/2)):
        if s[i] != s[leng-i-1]:
            count += 1
    
print(count)

Solution (Python):
S = input()
x =0
for i in range(len(S)//2):
	if S[i]!=S[-i-1]:x+=1
print(x)

Solution (Python):
S = input()
N = len(S)
cnt = 0
for i in range(N//2):
    if S[i] != S[N-1-i]:
        cnt += 1

print(cnt)

Solution (Python):
S = input()
length = len(S)
L = length//2
if length%2==0:
    A = S[:L]
    B = S[L:]
else:
    A = S[:L]
    B = S[L+1:]
hug = 0
for i in range(L):
    if A[i] != B[::-1][i]:
        hug += 1
print(hug)

Solution (Python):
s=input()
n=len(s)
ans = 0
if n % 2 == 0:
  for i in range(n//2):
    ans += (s[i] != s[-i-1])
else:
  for i in range((n-1)//2):
    ans += (s[i] != s[-i-1])
print(ans)

Solution (Python):
S = input()
n = len(S)
ans = 0
for i in range(n):
    if S[i] != S[n-1-i]:
        ans += 1

print(int(ans/2))