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)

//package atcoder.beginner_172;

import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;
import java.util.StringTokenizer;

public class Main {

    public static void main (String[] args) throws Exception {

        String s = "2";

//        br = new BufferedReader(new StringReader(s));
        br = new BufferedReader(new InputStreamReader(System.in));
        bw = new BufferedWriter(new OutputStreamWriter(System.out));

        rl(); char[] S=nca(), T=nca();
        int c=0;
        for (int i=0; i<S.length; ++i) if (S[i]!=T[i]) ++c;
        
        bw.write(Integer.toString(c));
        bw.newLine();
        bw.flush();

    }

    static BufferedReader br;
    static BufferedWriter bw;
    static StringTokenizer st;
    static void rl() throws Exception{
        st = new StringTokenizer(br.readLine());
    }
    static long nlo(){
        return Long.parseLong(st.nextToken());
    }
    static int nin(){
        return Integer.parseInt(st.nextToken());
    }
    /*private static void te(){
      }*/
    static double ndo(){
        return Double.parseDouble(st.nextToken());
    }
    static char[] nca(){
        return st.nextToken().toCharArray();
    }
    static String nstr(){
        return st.nextToken();
    }
}