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 Scala (2.13.1) (judge verdict: Accepted)

object Main extends App {
    val stdin = new java.util.Scanner(new java.io.BufferedInputStream(System.in))
    val stdout = new java.io.PrintWriter(new java.io.BufferedOutputStream(System.out))

    while (stdin.hasNext()) {
        val lhs = stdin.next()
        val rhs = stdin.next()
        val foo = (p:Int) => lhs(p) == rhs(p) : Boolean
        val bar = (0 to lhs.length() - 1).filterNot(foo).size : java.lang.Integer
        stdout.printf("%d\n", bar)
    }

    stdin.close()
    stdout.close()
}