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 Kotlin (1.3.71) (judge verdict: Accepted)

import java.io.PrintWriter
import java.util.StringTokenizer

fun main() {

    fun PrintWriter.solve() {
        var s = next()
        var t = next()

        var ans = s.zip(t).filter { it.first != it.second }.count()
        println(ans)

    }

    writer.solve()
    writer.flush()


}


private val reader = System.`in`.bufferedReader()
private val writer = PrintWriter(System.out, false)

private var tokenizer: StringTokenizer = StringTokenizer("")

private fun next(): String {
    while (tokenizer.hasMoreTokens().not()) tokenizer = StringTokenizer(reader.readLine())
    return tokenizer.nextToken()
}

private fun nextInt() = next().toInt()
private fun nextLong() = next().toLong()
private fun nextDouble() = next().toDouble()
private fun nextLine() = reader.readLine()