import java.util.Scanner;
class Main {
    static Scanner scan = new Scanner(System.in);
    public static void main(String[] args) {
        String S = scan.next();
        String T = scan.next();
        int i = 0;
        int j = 0;
        int count = 0;
        while(i < S.length() && j < T.length()) {
            if(S.charAt(i) != T.charAt(j)){
                count++;
            }
            i++;
            j++;
        }
        System.out.println(count);
    }
} import java.util.Scanner; Scanner java.util class Main {
    static Scanner scan = new Scanner(System.in);
    public static void main(String[] args) {
        String S = scan.next();
        String T = scan.next();
        int i = 0;
        int j = 0;
        int count = 0;
        while(i < S.length() && j < T.length()) {
            if(S.charAt(i) != T.charAt(j)){
                count++;
            }
            i++;
            j++;
        }
        System.out.println(count);
    }
} Main static Scanner scan = new Scanner(System.in); scan new Scanner(System.in) public static void main(String[] args) {
        String S = scan.next();
        String T = scan.next();
        int i = 0;
        int j = 0;
        int count = 0;
        while(i < S.length() && j < T.length()) {
            if(S.charAt(i) != T.charAt(j)){
                count++;
            }
            i++;
            j++;
        }
        System.out.println(count);
    } main {
        String S = scan.next();
        String T = scan.next();
        int i = 0;
        int j = 0;
        int count = 0;
        while(i < S.length() && j < T.length()) {
            if(S.charAt(i) != T.charAt(j)){
                count++;
            }
            i++;
            j++;
        }
        System.out.println(count);
    } String S = scan.next(); S scan.next() scan.next scan String T = scan.next(); T scan.next() scan.next scan int i = 0; i 0 int j = 0; j 0 int count = 0; count 0 while(i < S.length() && j < T.length()) {
            if(S.charAt(i) != T.charAt(j)){
                count++;
            }
            i++;
            j++;
        } i < S.length() && j < T.length() i < S.length() i S.length() S.length S j < T.length() j T.length() T.length T {
            if(S.charAt(i) != T.charAt(j)){
                count++;
            }
            i++;
            j++;
        } if(S.charAt(i) != T.charAt(j)){
                count++;
            } S.charAt(i) != T.charAt(j) S.charAt(i) S.charAt S i T.charAt(j) T.charAt T j {
                count++;
            } count++ count i++ i j++ j System.out.println(count) System.out.println System.out System System.out count String[] args args
import java.util.Scanner;
class Main {
    static Scanner scan = new Scanner(System.in);
    public static void main(String[] args) {
        String S = scan.next();
        String T = scan.next();
        int i = 0;
        int j = 0;
        int count = 0;
        while(i < S.length() && j < T.length()) {
            if(S.charAt(i) != T.charAt(j)){
                count++;
            }
            i++;
            j++;
        }
        System.out.println(count);
    }
}
