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)

private fun readLn() = readLine()!!
private fun readInt() = readLn().toInt()
private fun readStrings() = readLn().split(" ")
private fun readInts() = readStrings().map(String::toInt)
private fun readStrings2() = readLn().split("").filter { it.isNotEmpty() }
private fun readInts2() = readStrings2().map(String::toInt)
private fun initArray(n:Int, v:String) = Array(n) { v }
private fun initIntArray(n:Int, v:Int) = IntArray(n) { v }

fun main(args: Array<String>) {
    val S = readStrings2()
    val T = readStrings2()

    var cnt = 0

    for (i in S.indices) {
        if(S[i] != T[i]) {
            cnt += 1
        }
    }

    println(cnt)
}