Given are strings S and T. Consider changing S to T by repeating the operation below. Find the minimum number of operations required to do so.
Operation: Choose one character of S and replace it with a different character.

-----Constraints-----
 - S and T have lengths between 1 and 2\times 10^5 (inclusive).
 - S and T consists of lowercase English letters.
 - S and T have equal lengths.

-----Input-----
Input is given from Standard Input in the following format:
S
T

-----Output-----
Print the answer.

-----Sample Input-----
cupofcoffee
cupofhottea

-----Sample Output-----
4

We can achieve the objective in four operations, such as the following:
 - First, replace the sixth character c with h.
 - Second, replace the eighth character f with t.
 - Third, replace the ninth character f with t.
 - Fourth, replace the eleventh character e with a.

Difficulty: introductory

Starter code:

Solutions:
S = input()
T = input()
tigau = 0

for i in range(len(S)):
  if S[i] != T[i]:
    tigau += 1

print(tigau)


s = input()
t = input()

ans = 0

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

print(ans)


s = input()
t = input()

count = 0
for i,j in enumerate(s):
  if j != t[i]:
    count += 1
print(count)

s = input()
t = input()
ans = 0

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

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

s = input() 
t = input()
ans = 0
for i in range(len(s)):
    if s[i] != t[i]:
        ans += 1

print(ans)

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

def main():
    s = input()
    t = input()
    ans = 0
    for i in range(len(s)):
        if s[i] != t[i]:
            ans += 1
    print(ans)
    return


def __starting_point():
    main()

__starting_point()

S = str(input())
T = str(input())


result = 0

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

S=input()
T=input()

N=len(S)

ans=0
for i in range(N):
    if S[i]!=T[i]:
        ans+=1
print(ans)

#                               #
    # author : samars_diary #
    # 17-09-2020 │ 20:30:32 #
#                               #

import sys, os.path

#if(os.path.exists('input.txt')):
    #sys.stdin = open('input.txt',"r")
    #sys.stdout = open('output.txt',"w")

sys.setrecursionlimit(10 ** 5)

def mod(): return 10**9+7
def i(): return sys.stdin.readline().strip()
def ii(): return int(sys.stdin.readline())
def li(): return list(sys.stdin.readline().strip())
def mii(): return map(int, sys.stdin.readline().split())
def lii(): return list(map(int, sys.stdin.readline().strip().split()))

#print=sys.stdout.write

def solve():
    a=li();b=li();c=0
    for i in range(len(a)):
        if a[i]!=b[i]:
            c+=1
    print(c)
for _ in range(1):
    solve()

S = input()
T = input()

l = len(S)
count = 0

for i in range(l):
    if S[i] != T[i]:
        count += 1
print(count)

S = input()
T = input()
p = 0

for i in range(0,len(S)):
    if S[i] == T[i]:
        pass
    else:
        p += 1

print(p)

S = input()
T = input()
count = 0

for s, t in zip(S, T):
    if s != t:
        count += 1

print(count)

def main():
    s = input()
    t = input()
    ans = 0
    
    for i, j in zip(s, t):
        if i != j:
            ans += 1
    print(ans)
        
        
def __starting_point():
    main()
__starting_point()

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


str1 = input()
str2 = input()

idx = 0
cnt = 0
for _ in range(len(str1)):
    if str1[idx] != str2[idx]:
        cnt += 1
    idx += 1

print(cnt)

s = input()
t = input()

count = 0

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

print(count)


S = input()
T = input()

print((sum(i != j for i,j in zip(S,T))))



S = input()
T = input()

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

S = input()
T = input()
l = len(S)
C = 0
for i in range(l):
  if not S[i]==T[i]:
    C = C +1
print(C)

# -*- coding: utf-8 -*-
"""
Created on Fri Sep 18 19:19:52 2020

@author: ezwry
"""

s=list(input())
t=list(input())
u=len(s)
ans=0
for i in range(u):
    if s[i] != t[i]:
        ans+=1
    
print(ans)

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

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

S = list(input())
T = list(input())
count = len(S)
ans = 0

for i in range(count):
  if S[i] != T[i]:
    ans += 1
  else: 
    pass

print(ans)

S=input()
T=input()

count=0

for i in range(len(S)):
  if S[i] != T[i]:
    count+=1
print(count)

S = str(input())
T = str(input())
cnt = 0
for i in range(len(S)):
  if S[i] != T[i]:
    cnt += 1
print(cnt)

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

S = input()
T = input()

D = 0

for i in range(len(S)):
    if S[i] != T[i]:
        D += 1

print(D)

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


import math,string,itertools,fractions,heapq,collections,re,array,bisect,sys,random,time, copy,bisect
#from operator import itemgetter
#from heapq import heappush, heappop
#import numpy as np
#import sympy
#from scipy.sparse.csgraph import breadth_first_order, depth_first_order, shortest_path, floyd_warshall, dijkstra, bellman_ford, johnson
#from scipy.sparse import csr_matrix
from decimal import Decimal, ROUND_HALF_UP, ROUND_HALF_EVEN
import sys

sys.setrecursionlimit(10**7)
inf = 10**20
mod = 10**9 + 7

stdin = sys.stdin

ni = lambda: int(ns())
nf = lambda: float(ns())
na = lambda: list(map(int, stdin.readline().split()))
nb = lambda: list(map(float, stdin.readline().split()))
ns = lambda: stdin.readline().rstrip()  # ignore trailing spaces

S = ns()
T = ns()
ans = 0
for s, t in zip(S, T):
    if s != t:
        ans += 1
print(ans)

S,T = input(),input()
count=0
for i,j in zip(S,T):
  if i!=j:count+=1
print(count)

s = list(input())
t = list(input())

count = 0
for i in range(len(s)) :
    if s[i]==t[i] :
        continue
    elif s[i]!=t[i] :
        t[i] = s[i]
        count += 1
        
print(count)

s=input()
t=input()

cot = 0
for i in range(len(s)):
    if s[i] == t[i]:
        cot += 1
print(len(s)-cot)  

s=input(); t=input();
print(sum([s[i]!=t[i] for i in range(len(s))]))

s=input()
t=input()
count=0
for i in range(0,len(s)):
    if(s[i]==t[i]):
        continue
    else:
        count+=1
print(count)

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

S=input()
T=input()
R=len(S)
A=0
for k in range(R) :
    if S[k-1]!=T[k-1]:
        A+=1
print(A)

s = str(input())
t = str(input())
l = len(s)
c = 0
for i in range(l):
    if s[i] != t[i]:
        c += 1
print(c)


n = str(input())
m = str(input())
ans = 0
for i in range(len(n)):
    if n[i] != m[i]:
        ans+=1
print(ans)

s = input()
t = input()
cnt = 0

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

print(cnt)


S, T = input(), input()
cnt = 0
for i in range(len(S)):
  if S[i] != T[i]:
    cnt += 1
print(cnt)

S=input()
T=input()

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

print(sum(x != y for x, y in zip(input(), input())))

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

S = input()
T = input()
count = 0
for i in range(len(S)):
    if S[i] != T[i]:
        count = count + 1
print(count)

s = input()
t = input()
if s == t:
    print((0))
else:
    p = -1
    ans = 0
    for i in s:
        p += 1
        if i != t[p]:
            ans += 1
    print(ans)


s = input()
t = input()
ln = len(s)
cnt = 0
for i in range(ln):
    if s[i] != t[i]:
        cnt += 1
print(cnt)


S = input()
T = input()
retval = len(S)
for i in range(len(S)):
  if(S[i]==T[i]):
    retval-=1
print(retval)

print(sum(s!=t for s,t in zip(*open(0))))

def function():
	pass
	S=input()
	T=input()

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

function()

s = input()

t = input()

ans = 0

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

print(ans)

s = input()
t = input()
ans = 0
for s, t in zip(s, t):
    if s != t:
        ans += 1
print(ans)

str1 = input()
str2 = input()

count = 0
for i in range(len(str1)):
  if(str1[i] != str2[i]):
    count+=1
    
print(count)

S = input()
T = input()
l = len(S)
ans = 0

for i in range(l):
    if S[i] != T[i]:
        ans += 1

print(ans)

def answer(s: str, t: str) -> int:
    count = 0
    for i in range(len(s)):
        if s[i] != t[i]:
            count += 1
            
    return count


def main():
    s = input()
    t = input()
    print((answer(s, t)))


def __starting_point():
    main()

__starting_point()

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


a = list(str(input()))
b = list(str(input()))
count=0
for i in range(len(a)):
    if a[i] != b[i]:
        count +=1
print(count)


import sys
from collections import deque, defaultdict, Counter
from itertools import accumulate, product, permutations, combinations
from operator import itemgetter
from bisect import bisect_left, bisect_right
from heapq import heappop, heappush
from math import ceil, floor, sqrt, gcd, inf
from copy import deepcopy
import numpy as np
import scipy as sp

INF = inf
MOD = 1000000007

s = input()
t = input()

tmp = 0
res = 0

for i, j in zip(s, t):
    if i != j:
        res += 1

print(res)


s = str(input())
t = str(input())
score = 0
le = len(s)

for i in range(le):
    if s[i] != t[i]:
        score += 1

print(score)

S = input()
T = input()
count=0
for i in range(len(S)):
  if S[i] == T[i]:
    count+=1
print(len(T)-count)    

s = input()
t = input()
n = len(s)
a = 0

for i in range(n):
  if s[i] != t[i]:
    a += 1
    
print(a)

S = input()
T = input()
s = 0
for i in range(len(S)):
  if S[i] != T[i]:
    s += 1
print(s)

S = input()
T = input()

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

print(cnt)


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

s = input()
t = input()
ans = 0

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

print(ans)



s = input()
t = input()


def counts(s, t):
    cnt = 0
    length = len(s)
    for i in range(length):
        if s[i] != t[i]:
            cnt += 1
    return cnt


print((counts(s, t)))


S = input()
T = input()
cnt = 0
for i in range (len(S)):
  if(S[i] == T[i]):continue
  else: cnt = cnt + 1 
print(cnt)

S = input()
T = input()

cnt = 0

for i in range(len(S)):
    if S[i] != T[i]:
        cnt += 1

print(cnt)


a = list(input())
b = list(input())

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


s = input()
t = input()
S = [x for x in s]
T = [y for y in t]
count = 0
for i in range(len(s)):
    if S[i] != T[i]:
        count += 1
print(count)

s = input()
t = input()

count = int(0)

for i in range(len(s)):
    if not s[i] == t[i]:
        count += 1

print(count)

s = input()
t = input()

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


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

s = input()
t = input()

count = 0
for ss, tt in zip(s, t):
  if ss != tt:
    count += 1

print(count)

def ans172(S:str, T:str):
    ans_count=0
    for i in range(len(S)):
        if S[i]!=T[i]:
            ans_count+=1
    return ans_count

def __starting_point():
    S=input()
    T=input()
    print(ans172(S,T))
__starting_point()

s = input()
t = input()
c = 0

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

print(c)

s = [i for i in input()]
t = [j for j in input()]
count = 0
for k, l in zip(s, t):
  if k != l:
    count += 1
print(count)

S = list(input())
T = list(input())

ans = 0

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

print(ans)

S = input()
T = input()
count = 0
for i in range(len(S)):
  if S[i] != T[i]:
    count += 1
print(count)

s = input()
t = input()
c = 0
for i,j in zip(s,t):
  if i!=j:
    c += 1
print(c)

n = list(input())
n1 = list(input())

i = 0
cou = 0
while i != len(n):
    if n[i] != n1[i]:
        cou += 1
    i += 1

print(cou)

S = input()
T = input()

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

print(count)

ss = list(input())
tt = list(input())
cnt = 0
for i in range(len(ss)):
  if ss[i] != tt[i]:
    cnt += 1
print(cnt)

#!/usr/bin/env python3
import sys
sys.setrecursionlimit(1000000)
from collections import deque

S =input()
T =input()
l = len(S)
count = 0
for i in range(l):
    if S[i] != T[i]:
        count += 1

print(count)

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

s = input()
t = input()
print(sum(i != j for i, j in zip(s, t)))

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

a = input().split()[0]
str = input().split()[0]
count = 0
for i in range(len(a)):
    if(str[i] != a[i]):
        count = count + 1
print(count)


S = input()
T = input()
ans = 0
for s, t in zip(S, T):
  if s != t: ans += 1;
print(ans)

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

S = input()
T = input()
count = 0

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

print(count)

s = list(map(str, input()))
t = list(map(str, input()))

ans = 0

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

print(ans)


s = list(input())
t = list(input())
ans = 0

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

print(ans)

s = input()
t = input()
ls = list(s)
lt = list(t)
result = 0
for data in range(len(ls)):
    if ls[data] != lt[data]:
        result += 1
print(result)


S = input()
T = input()

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

s=list(input())
t=list(input())
o=0
for (i,j) in zip(s,t):
    if i!=j:
        o+=1
print(o)

S = input()
T = input()
count = 0
for i in range(len(S)):
  if S[i] != T[i]:
    count += 1
print(count)

print(sum([x!=y for x,y in zip(input(),input())]))