Problem:
Score : 200 points

Problem Statement

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 1

cupofcoffee
cupofhottea

Sample Output 1

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.

Sample Input 2

abcde
bcdea

Sample Output 2

5

Sample Input 3

apple
apple

Sample Output 3

0

No operations may be needed to achieve the objective.

Solution in Go (1.14.1) (judge verdict: Accepted)

package main

import (
"fmt"
"strings"
)

func main() {
	var s1, t1 string
	s := make([]string, 200000)
	t := make([]string, 200000)
	_, _ = fmt.Scan(&s1, &t1)
	s1 = strings.ToLower(s1)
	t1 = strings.ToLower(t1)

	s = strings.Split(s1, "")
	t = strings.Split(t1, "")

	a := 0
	for i:=0; i<len(s); i++ {
		if s[i]!=t[i] {
			a++
		}
	}

	fmt.Println(a)
}