import java.util.Scanner;

public class Main {
    public static void main(String args[]){
        Scanner sc = new Scanner(System.in);
        String text1 = sc.nextLine();
        String text2 = sc.nextLine();

        int wordNum = text1.length();
        int diffCount=0;

        for(int i=0;i<wordNum;i++){
            if(text1.charAt(i) != text2.charAt(i)){
                diffCount +=1;
            }
        }
        System.out.println(diffCount);
    }
} import java.util.Scanner; Scanner java.util public class Main {
    public static void main(String args[]){
        Scanner sc = new Scanner(System.in);
        String text1 = sc.nextLine();
        String text2 = sc.nextLine();

        int wordNum = text1.length();
        int diffCount=0;

        for(int i=0;i<wordNum;i++){
            if(text1.charAt(i) != text2.charAt(i)){
                diffCount +=1;
            }
        }
        System.out.println(diffCount);
    }
} Main public static void main(String args[]){
        Scanner sc = new Scanner(System.in);
        String text1 = sc.nextLine();
        String text2 = sc.nextLine();

        int wordNum = text1.length();
        int diffCount=0;

        for(int i=0;i<wordNum;i++){
            if(text1.charAt(i) != text2.charAt(i)){
                diffCount +=1;
            }
        }
        System.out.println(diffCount);
    } main {
        Scanner sc = new Scanner(System.in);
        String text1 = sc.nextLine();
        String text2 = sc.nextLine();

        int wordNum = text1.length();
        int diffCount=0;

        for(int i=0;i<wordNum;i++){
            if(text1.charAt(i) != text2.charAt(i)){
                diffCount +=1;
            }
        }
        System.out.println(diffCount);
    } Scanner sc = new Scanner(System.in); sc new Scanner(System.in) String text1 = sc.nextLine(); text1 sc.nextLine() sc.nextLine sc String text2 = sc.nextLine(); text2 sc.nextLine() sc.nextLine sc int wordNum = text1.length(); wordNum text1.length() text1.length text1 int diffCount=0; diffCount 0 for(int i=0;i<wordNum;i++){
            if(text1.charAt(i) != text2.charAt(i)){
                diffCount +=1;
            }
        } int i=0; int i=0; i 0 i<wordNum i wordNum i++ i++ i {
            if(text1.charAt(i) != text2.charAt(i)){
                diffCount +=1;
            }
        } {
            if(text1.charAt(i) != text2.charAt(i)){
                diffCount +=1;
            }
        } if(text1.charAt(i) != text2.charAt(i)){
                diffCount +=1;
            } text1.charAt(i) != text2.charAt(i) text1.charAt(i) text1.charAt text1 i text2.charAt(i) text2.charAt text2 i {
                diffCount +=1;
            } diffCount +=1 diffCount 1 System.out.println(diffCount) System.out.println System.out System System.out diffCount String args[] args public class Main {
    public static void main(String args[]){
        Scanner sc = new Scanner(System.in);
        String text1 = sc.nextLine();
        String text2 = sc.nextLine();

        int wordNum = text1.length();
        int diffCount=0;

        for(int i=0;i<wordNum;i++){
            if(text1.charAt(i) != text2.charAt(i)){
                diffCount +=1;
            }
        }
        System.out.println(diffCount);
    }
} public class Main {
    public static void main(String args[]){
        Scanner sc = new Scanner(System.in);
        String text1 = sc.nextLine();
        String text2 = sc.nextLine();

        int wordNum = text1.length();
        int diffCount=0;

        for(int i=0;i<wordNum;i++){
            if(text1.charAt(i) != text2.charAt(i)){
                diffCount +=1;
            }
        }
        System.out.println(diffCount);
    }
} Main
import java.util.Scanner;

public class Main {
    public static void main(String args[]){
        Scanner sc = new Scanner(System.in);
        String text1 = sc.nextLine();
        String text2 = sc.nextLine();

        int wordNum = text1.length();
        int diffCount=0;

        for(int i=0;i<wordNum;i++){
            if(text1.charAt(i) != text2.charAt(i)){
                diffCount +=1;
            }
        }
        System.out.println(diffCount);
    }
}