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 Java (OpenJDK 11.0.6) (judge verdict: Accepted)

import java.util.Scanner;

public class Main {
  public static void main(String[] args){
      Scanner sc = new Scanner(System.in);
      // 文字列の入力1
      String str1 = sc.nextLine();
      // 文字列の入力1
      String str2 = sc.nextLine();
      if(!str1.equals(str2)) {
        int count = 0;
        for(int i = 0;i<str1.length();i++) {
          if(str1.charAt(i)!= str2.charAt(i)) {
            count++;
          }
        }
        System.out.println(count);
      }else {
        System.out.println(0);
      }
  }
}