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: Runtime Error)

import java.util.Scanner;
public class Main{
	public static void main(String[] args){
		Scanner ss = new Scanner(System.in);
		Scanner st = new Scanner(System.in);
		
		String s = ss.nextLine();
		String t = st.nextLine();
		
		int count=0;
		
		char[] sstri= s.toCharArray();
		char[] tstri= t.toCharArray();
		
		for(int i=0;i<=sstri.length;i++){
			if(i==sstri.length){
				System.out.print(count);
			}
			else if(sstri[i] != tstri[i]){
				sstri[i] = tstri[i];
				count++;
			}
		}
	}
}