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()
s = list(s)
s_r = list(reversed(s))
n = len(s)
c = 0
for i in range(n // 2):
    if s[i] != s_r[i]:
        c += 1
ans = c
print(ans)

Solution (Python):
S = input()

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

print(cnt)

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


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

print(count)

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

Solution (Python):
import sys
input = sys.stdin.readline
S = list(input())[ :-1]
T = S[: : -1]
res = 0
for i in range(len(S)):
  if S[i] != T[i]:
    res += 1
    S[i] = T[i]
    T[-1 - i] = S[i]
  
print(res)

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

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

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

for i in range(len(s)//2):
  ans += not s[i]==s[-1-i]
print(ans)

Solution (Python):
S=input()
l=len(S)
cnt=0

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

print(cnt)

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

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

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

Solution (Python):
from sys import stdin

S = stdin.readline().rstrip()
c = len(S) // 2
ans = 0

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

print(ans)

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

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


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):
s = str(input())
sl = [str(i) for i in s]
cnt = 0

for i in range(len(sl)//2):
    if sl[i] == sl[len(sl)-1-i]:
        pass
    else:
        cnt += 1

print(cnt)

Solution (Python):
S = list(input())
left = S[0:len(S)//2]
right = S[len(S)//2:]
right.reverse()
cnt = 0
for l,r in zip(left,right):
  if l != r:
    cnt += 1
print(cnt)

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

Solution (Python):
s = input()

cnt = 0

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

Solution (Python):
s = input()
l = len(s)
if l%2 == 1:
    b = s[:l//2]
    a = s[l//2+1:][::-1]
else:
    b = s[:l//2]
    a = s[l//2:][::-1]
count = 0
for x,y in zip(b, a):
    if x != y:
        count += 1
print(count)

Solution (Python):
S=raw_input()

ans=0
for x,y in zip(S,S[::-1]):
    if x!=y:
        ans+=1
print ans/2

Solution (Python):
S = list(input())
n = len(S)
r = S[:n//2]
l = S[n-n//2:]
l.reverse()
c = 0
for i, j in zip(r, l):
    if i != j:
        c += 1
print(c)

Solution (Python):
s = input()
n = len(s) // 2
res = 0
for a, b in zip(s[:n], reversed(s[-n:])):
    if a != b:
        res += 1
print(res)

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

Solution (Python):
S = input()

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

print(counter)

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

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

Solution (Python):
S = input()
half=len(S)//2

rS = list(reversed(S))


cnt=0
for i in range(half):
  if S[i] != rS[i]:
    cnt += 1

print(cnt)

Solution (Python):
s = input()
l = len(s)
num = int(l / 2)

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

print(count)

Solution (Python):
S = input()
if len(S)%2 == 0:
    tmp1 = S[:len(S)//2]
    tmp2 = S[len(S)//2:]
    tmp2 = tmp2[::-1]
    count = 0
    for i in range(len(tmp1)):
        if tmp1[i] != tmp2[i]:
            count += 1
    print(count)
else:
    tmp1 = S[:len(S)//2]
    tmp2 = S[len(S)//2+1:]
    tmp2 = tmp2[::-1]
    count = 0
    for i in range(len(tmp1)):
        if tmp1[i] != tmp2[i]:
            count += 1
    print(count)

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

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

S1 = S[:N//2]
S2 = S[-(N//2):]
S2 = S2[::-1]
ans = 0
for i in range(len(S1)):
    if S1[i] != S2[i]:
        ans += 1
print(ans)

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):
s = input()

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

print(ans)

Solution (Python):
S = input().strip()

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

print(ans)

Solution (Python):



import numpy as np

str = input()

count = 0

for n in range(int(np.floor(len(str)/2))):
    if str[n] != str[-1-n]:
        count += 1

print(count)

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

print(count)

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

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

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

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

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

ans = 0

for i in range(0, len(s)//2):
  if s[i] != s[len(s)-1-i]:
    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):
def main():
    s=input()
    low=0
    high=len(s)-1
    cnt=0
    while low<high:
        if s[low]!=s[high]:
            cnt+=1
        low+=1
        high-=1
    print(cnt)

if __name__=='__main__':
    main()

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

Solution (Python):
import sys, re
from collections import deque, defaultdict, Counter
from math import ceil, sqrt, hypot, factorial, pi, sin, cos, radians
from itertools import permutations, combinations, product, accumulate
from operator import itemgetter, mul
from copy import deepcopy,copy
from string import ascii_lowercase, ascii_uppercase, digits
from fractions import gcd

def input(): return sys.stdin.readline().strip()
def INT(): return int(input())
def MAP(): return map(int, input().split())
def LIST(): return list(map(int, input().split()))
sys.setrecursionlimit(10 ** 9)
INF = float('inf')
mod = 10 ** 9 + 7

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

if __name__=='__main__':
	main()

Solution (Python):
s = input()

l = len(s)

if l % 2 == 0:
    s1 = s[0:l//2]
    s2 = s[l//2:]
else:
    s1 = s[0:l//2]
    s2 = s[l//2+1:]

s2 = s2[::-1]

cnt = 0
for x, y in zip(s1, s2):
    if x != y:
        cnt += 1

print(cnt)

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

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

if __name__ == '__main__':
    main()

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):
ni = lambda: int(input())
nm = lambda: map(int, input().split())
nl = lambda: list(map(int, input().split()))


s = input()

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


print(cnt)

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

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

print(count)

Solution (Python):
import sys

s = sys.stdin.readline().rstrip()
l = len(s)
def main():
    cnt = 0
    for i in range(l // 2):
        if s[i] != s[-i-1]:
            cnt += 1

    return cnt

if __name__ == '__main__':
    ans = main()
    print(ans)

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()

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

print(ans // 2)

Solution (Python):
from sys import stdin
S = (stdin.readline().rstrip())
l=len(S)
ans = 0
for i in range(l//2):
    if S[i] != S[::-1][i]:
        ans += 1
print(ans)

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

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

Solution (Python):
s = input()

left = 0
right = len(s) - 1
ans = 0

while left < right:
    if s[left] != s[right]:
        ans += 1
    left += 1
    right -= 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 = list(x for x in input())
ans = 0

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

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

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

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()
s_front = S[:len(S)//2]
s_back = reversed(S[-(len(S)//2):])

ans = 0

for f, b in zip(s_front, s_back):
  if f != b:
    ans += 1
print(ans)

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

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

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

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

if N%2==0:
  s1 = S[:N//2]
  s2 = S[N//2:][::-1]
else:
  s1 = S[:N//2]
  s2 = S[N//2+1:][::-1]

answer = 0
for i in range(N//2):
  if s1[i]!=s2[i]:
    answer += 1
print(answer)

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

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

print(ans)

Solution (Python):
S = str(input())
x = int(len(S)//2)
count = 0

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

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

Solution (Python):


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

print(summ)

Solution (Python):
s=input()

s=list(s)

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

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

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

count = 0

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

print(count)

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

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

Solution (Python):
import sys

sys.setrecursionlimit(10**7)
INF = 10 ** 18
MOD = 10 ** 9 + 7
def LI(): return list(map(int, sys.stdin.readline().split()))
def II(): return int(sys.stdin.readline())
def LS(): return list(map(list, sys.stdin.readline().split()))
def S(): return list(sys.stdin.readline())[:-1]

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

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

print(cnt)

Solution (Python):
S = raw_input()

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

print ans

Solution (Python):
def main():
    S = input()
    count = 0
    for i in range(len(S)//2):
        if S[i] == S[len(S) - i - 1]:
            continue
        else:
            count += 1

    print(count)


if __name__ == '__main__':
    main()

Solution (Python):
S = input()

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

print(count)

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

Solution (Python):
S=input()

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

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

Solution (Python):
str = input()

str1 = str
str2 = str[::-1]

count = 0

for i in range(len(str1) // 2):
  if str1[i] != str2[i]:
    count += 1

print(count)

Solution (Python):
import sys

sys.setrecursionlimit(4100000)


def inputs(num_of_input):
    ins = [input() for i in range(num_of_input)]
    return ins


def solve(inputs):
    S = inputs[0]
    n = len(S)
    is_even = True if n % 2 == 0 else False

    if is_even:
        front = S[:n//2]
        back = S[n//2:]
    else:
        front = S[:n//2+1]
        back = S[n//2:]
    count = 0

    for i, c in enumerate(reversed(back)):
        if front[i] != c:
            count += 1
    return count


def string_to_int(string):
    return list(map(lambda x: int(x), string.split()))


if __name__ == "__main__":
    ret = solve(inputs(1))
    print(ret)

Solution (Python):
s = input()
ans = 0
if len(s) %2 != 0:
    a = len(s)//2
    list1 = s[:a]
    list2 = s[a+1:]
    for i in range(a):
        if list1[i] != list2[-(i+1)]:
            ans +=1

else:
    a = len(s)//2
    list1 = s[:a]
    list2 = s[a:]
    for i in range(a):
        if list1[i] != list2[-(i+1)]:
            ans +=1


print(ans)

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

Solution (Python):
S=input()

c=0

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

print(c)

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

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

Solution (Python):
s = str(input())
i = 0
hug = 0
while (i < (len(s))/2):
    if (s[i] != s[len(s)-1-i]):
        hug += 1
    i += 1
print (hug)

Solution (Python):
from heapq import heappush, heappop, heapify
from collections import deque, defaultdict, Counter
import itertools
from itertools import permutations, combinations, accumulate
import sys
import bisect
import string
import math
import time
from fractions import gcd



def I(): return int(input())


def MI(): return map(int, input().split())


def LI(): return [int(i) for i in input().split()]


def LI_(): return [int(i)-1 for i in input().split()]


def StoI(): return [ord(i)-97 for i in input()]


def ItoS(nn): return chr(nn+97)


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


def show(*inp, end='\n'):
    if show_flg:
        print(*inp, end=end)


YN = ['No', 'Yes']
MOD = 10**9+7
inf = float('inf')
IINF = 10**10
l_alp = string.ascii_lowercase
u_alp = string.ascii_uppercase
ts = time.time()
sys.setrecursionlimit(10**6)
nums = ['1', '2', '3', '4', '5', '6', '7', '8', '9', '10']

show_flg = False



def main():
    S = input()
    stack = []
    ans = 0

    for i in range(len(S)//2):
        stack.append(S[i])

    start = 0
    if len(S) % 2 == 1:
        start = 1

    for i in range(len(S)//2+start, len(S)):
        a = stack.pop()
        if a != S[i]:
            ans += 1

    print(ans)



if __name__ == '__main__':
    main()

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

Solution (Python):
s = input()

length = len(s)

ans = 0

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

print(ans)

Solution (Python):
S = input()
start = 0
end = len(S)-1
cnt = 0
while start < end:
    if S[start] != S[end]:
        cnt += 1
    start += 1
    end -= 1
print(cnt)

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

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

print(cnt)

Solution (Python):


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

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

Solution (Python):
s=input()
n=len(s)
a=[]
b=[]
for i in range(n//2):
    a.append(s[i])
i=0
for i in range(n//2):
    b.append(s[n-1-i])
c=0
for i in range(n//2):
    if a[i]==b[i]:
        pass
    else:
        c+=1
print(c)

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

print(count)

Solution (Python):

import sys


def solve(S: str):
    answer = 0
    if len(S)%2 == 0:
        half  = len(S)//2
        for i in range(half,len(S)):
            if S[i] != S[len(S)-i-1]:
                answer += 1
    else:
        half  = len(S)//2
        for i in range(half+1,len(S)):
            if S[i] != S[len(S)-i-1]:
                answer += 1     
    print(answer)
    return


def main():
    def iterate_tokens():
        for line in sys.stdin:
            for word in line.split():
                yield word
    tokens = iterate_tokens()
    S = next(tokens)  
    solve(S)

if __name__ == '__main__':
    main()

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

Solution (Python):
s = input()
n = len(s)
s_inv = s[::-1]
count = 0
for i in range(int(n/2)):
    if s[i] != s_inv[i]:
        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()
from math import ceil
cnt = 0
for i in range(ceil(len(S)/2)):
    if S[i] != S[-i-1]:
        cnt += 1 
print(cnt)

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

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

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

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

print(count)

Solution (Python):
n = input()

k = len(n) //2
count = 0

for j in range(k):
    if n[j] != n[-(j+1)]:
        count += 1


print(count)

Solution (Python):
s = input()

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

Solution (Python):
def main():
    S = input()
    mid = len(S) // 2
    if len(S) % 2 == 0:
        a = S[:mid]
        b = S[mid:]
    else:
        a = S[:mid]
        b = S[mid+1:]

    b = b[::-1]
    ans = 0
    for i in range(mid):
        if a[i] != b[i]:
            ans += 1
    print(ans)

if __name__ == "__main__":
    main()

Solution (Python):
string = list(input())
print(sum(c1 != c2 for c1, c2 in zip(string[0:len(string) // 2], string[::-1][0:len(string) // 2])))

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

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

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

Solution (Python):

import sys


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



def main():
    def iterate_tokens():
        for line in sys.stdin:
            for word in line.split():
                yield word
    tokens = iterate_tokens()
    S = next(tokens)  
    solve(S)

if __name__ == '__main__':
    main()

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

Solution (Python):
s = input()

count = 0

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

print(count)

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

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

Solution (Python):
S = input()

i = 0
count = 0
q = len(S) - 1
while i < q:
    if S[i] != S[q]:
        count += 1
    i += 1
    q -= 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 = str(input())
i = 0
j = len(S) - 1
cnt = 0
while i < j:
    if S[i] != S[j]:
        cnt += 1
    i += 1
    j -= 1

print(cnt)

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

s1 = s[:n // 2]
s2 = s[(n + 1) // 2:]

ans = 0
for c1, c2 in zip(reversed(s1), s2):
  if c1 != c2:
    ans += 1

print(ans)

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

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

Solution (Python):
lst = list(input())
lst2 = lst[::-1]
cnt = 0
for i in range(len(lst)):
  if lst[i] != lst2[i]:
    cnt += 1
print(cnt//2)

Solution (Python):
s=input()

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

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

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

print(cnt)

Solution (Python):
S = input()

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

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

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

print(count)

Solution (Python):
def read():
    S = input().strip()
    return S, 

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


if __name__ == '__main__':
    inputs = read()
    print("%d" % solve(*inputs))

Solution (Python):
S=input()
S2=S[::-1]
ans=0
for i in range(len(S)):
  if S[i]!=S2[i]:
    ans+=1
print(ans//2)

Solution (Python):

import bisect
from collections import deque
import sys
sys.setrecursionlimit(10**6)
write = sys.stdout.write
dbg = lambda *something : print(*something) if DEBUG else 0
DEBUG = True

def index(a,b):
    return str(min(a,b)) + "," +  str(max(a, b))

def main(given = sys.stdin.readline):
    input = lambda : given().rstrip()
    LMIIS = lambda : list(map(int,input().split()))
    II = lambda : int(input())
    XLMIIS = lambda x : [LMIIS() for _ in range(x)]

    s = input()

    ans = 0

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

    print(ans)






if __name__ == '__main__':
    main()

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

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

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

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

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

Solution (Python):
s = input()
n = len(s)
m = n // 2 if not n % 2 else n // 2 + 1
cnt = 0

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

print(cnt)

Solution (Python):
s = input()
n = len(s) - 1
cnt = 0

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

print(cnt)

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

Solution (Python):
S = input()

S_R = S[::-1]

ans = 0
for s, sr in zip(S, S_R):
    if s != sr:
        ans += 1
        
print(ans//2)

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

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

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

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

print(count)

Solution (Python):
S = input()

n = len(S)
ans = 0

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

print(ans)

Solution (Python):


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

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

Solution (Python):
S = input()

l = 0
r = len(S)-1

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

Solution (Python):
S = input()

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

Solution (Python):
S = input()

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

print(answer)

Solution (Python):
S=input()
S1=S[::-1]
ans=0
for i in range(len(S)):
    if S[i]!=S1[i]: ans+=1
print(ans//2)

Solution (Python):
s = list(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)

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

Solution (Python):
s = str(input())
S = []
for i in s:
    S.append(i)

S_rev = S[::-1]

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

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


if __name__ == '__main__':
    solve()

Solution (Python):
import math
S = input()
N = len(S)
ans = 0

for i in range(math.ceil(N/2)):
  if S[i] != S[-1-i]:
    ans += 1
print(ans)

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

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

print(ans)

Solution (Python):
s = input()
l = len(s) // 2

ans = 0
for a, b in zip(s[:l], s[::-1]):
    if a != b:
        ans += 1

print(ans)

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

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

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

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

print(ans)