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 JavaScript (Node.js 12.16.1) (judge verdict: Time Limit Exceeded)

function Main (input) {
    input = input.split("\n");
    // var z = parseInt(input[0], 10);

    var s = input[0]
    var t = input[1]
    var z = []

    var cnt = 0
    var i = 0
    s.split("").forEach(char_s => {
        var char_t = t.split("")[i]

        if (char_s !== char_t) {
            cnt++
            z.push(char_t)
        } else {
            z.push(char_s)
        }

        var y = z.join("")

        if (t === y) {
            return
        }

        i++
    })

    console.log(cnt)
}

Main(require("fs").readFileSync("/dev/stdin", "utf8"));