import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        Scanner tan =new Scanner(System.in);
        while(tan.hasNext()){
            int i=0,sum=0;
            String s,t;
            s=tan.next();
            t=tan.next();
            char []a=new char[s.length()];
            char []b=new char[t.length()];
            for (char c : s.toCharArray()){
                a[i]=c;
                i++;
            }
            i=0;
            for (char ch : t.toCharArray()){
                b[i]=ch;
                i++;
            }
            for (int j = 0; j <t.length() ; j++) {
                if(a[j]!=b[j]){
                    sum++;
                }
            }
            System.out.println(sum);
        }
    }
} import java.util.Scanner; Scanner java.util public class Main {
    public static void main(String[] args) {
        Scanner tan =new Scanner(System.in);
        while(tan.hasNext()){
            int i=0,sum=0;
            String s,t;
            s=tan.next();
            t=tan.next();
            char []a=new char[s.length()];
            char []b=new char[t.length()];
            for (char c : s.toCharArray()){
                a[i]=c;
                i++;
            }
            i=0;
            for (char ch : t.toCharArray()){
                b[i]=ch;
                i++;
            }
            for (int j = 0; j <t.length() ; j++) {
                if(a[j]!=b[j]){
                    sum++;
                }
            }
            System.out.println(sum);
        }
    }
} Main public static void main(String[] args) {
        Scanner tan =new Scanner(System.in);
        while(tan.hasNext()){
            int i=0,sum=0;
            String s,t;
            s=tan.next();
            t=tan.next();
            char []a=new char[s.length()];
            char []b=new char[t.length()];
            for (char c : s.toCharArray()){
                a[i]=c;
                i++;
            }
            i=0;
            for (char ch : t.toCharArray()){
                b[i]=ch;
                i++;
            }
            for (int j = 0; j <t.length() ; j++) {
                if(a[j]!=b[j]){
                    sum++;
                }
            }
            System.out.println(sum);
        }
    } main {
        Scanner tan =new Scanner(System.in);
        while(tan.hasNext()){
            int i=0,sum=0;
            String s,t;
            s=tan.next();
            t=tan.next();
            char []a=new char[s.length()];
            char []b=new char[t.length()];
            for (char c : s.toCharArray()){
                a[i]=c;
                i++;
            }
            i=0;
            for (char ch : t.toCharArray()){
                b[i]=ch;
                i++;
            }
            for (int j = 0; j <t.length() ; j++) {
                if(a[j]!=b[j]){
                    sum++;
                }
            }
            System.out.println(sum);
        }
    } Scanner tan =new Scanner(System.in); tan new Scanner(System.in) while(tan.hasNext()){
            int i=0,sum=0;
            String s,t;
            s=tan.next();
            t=tan.next();
            char []a=new char[s.length()];
            char []b=new char[t.length()];
            for (char c : s.toCharArray()){
                a[i]=c;
                i++;
            }
            i=0;
            for (char ch : t.toCharArray()){
                b[i]=ch;
                i++;
            }
            for (int j = 0; j <t.length() ; j++) {
                if(a[j]!=b[j]){
                    sum++;
                }
            }
            System.out.println(sum);
        } tan.hasNext() tan.hasNext tan {
            int i=0,sum=0;
            String s,t;
            s=tan.next();
            t=tan.next();
            char []a=new char[s.length()];
            char []b=new char[t.length()];
            for (char c : s.toCharArray()){
                a[i]=c;
                i++;
            }
            i=0;
            for (char ch : t.toCharArray()){
                b[i]=ch;
                i++;
            }
            for (int j = 0; j <t.length() ; j++) {
                if(a[j]!=b[j]){
                    sum++;
                }
            }
            System.out.println(sum);
        } int i=0 i 0 sum=0; sum 0 String s s t; t s=tan.next() s tan.next() tan.next tan t=tan.next() t tan.next() tan.next tan char []a=new char[s.length()]; a new char[s.length()] s.length() s.length s char []b=new char[t.length()]; b new char[t.length()] t.length() t.length t for (char c : s.toCharArray()){
                a[i]=c;
                i++;
            } char c s.toCharArray() s.toCharArray s {
                a[i]=c;
                i++;
            } {
                a[i]=c;
                i++;
            } a[i]=c a[i] a i c i++ i i=0 i 0 for (char ch : t.toCharArray()){
                b[i]=ch;
                i++;
            } char ch t.toCharArray() t.toCharArray t {
                b[i]=ch;
                i++;
            } {
                b[i]=ch;
                i++;
            } b[i]=ch b[i] b i ch i++ i for (int j = 0; j <t.length() ; j++) {
                if(a[j]!=b[j]){
                    sum++;
                }
            } int j = 0; int j = 0; j 0 j <t.length() j t.length() t.length t j++ j++ j {
                if(a[j]!=b[j]){
                    sum++;
                }
            } {
                if(a[j]!=b[j]){
                    sum++;
                }
            } if(a[j]!=b[j]){
                    sum++;
                } a[j]!=b[j] a[j] a j b[j] b j {
                    sum++;
                } sum++ sum System.out.println(sum) System.out.println System.out System System.out sum String[] args args public class Main {
    public static void main(String[] args) {
        Scanner tan =new Scanner(System.in);
        while(tan.hasNext()){
            int i=0,sum=0;
            String s,t;
            s=tan.next();
            t=tan.next();
            char []a=new char[s.length()];
            char []b=new char[t.length()];
            for (char c : s.toCharArray()){
                a[i]=c;
                i++;
            }
            i=0;
            for (char ch : t.toCharArray()){
                b[i]=ch;
                i++;
            }
            for (int j = 0; j <t.length() ; j++) {
                if(a[j]!=b[j]){
                    sum++;
                }
            }
            System.out.println(sum);
        }
    }
} public class Main {
    public static void main(String[] args) {
        Scanner tan =new Scanner(System.in);
        while(tan.hasNext()){
            int i=0,sum=0;
            String s,t;
            s=tan.next();
            t=tan.next();
            char []a=new char[s.length()];
            char []b=new char[t.length()];
            for (char c : s.toCharArray()){
                a[i]=c;
                i++;
            }
            i=0;
            for (char ch : t.toCharArray()){
                b[i]=ch;
                i++;
            }
            for (int j = 0; j <t.length() ; j++) {
                if(a[j]!=b[j]){
                    sum++;
                }
            }
            System.out.println(sum);
        }
    }
} Main
import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        Scanner tan =new Scanner(System.in);
        while(tan.hasNext()){
            int i=0,sum=0;
            String s,t;
            s=tan.next();
            t=tan.next();
            char []a=new char[s.length()];
            char []b=new char[t.length()];
            for (char c : s.toCharArray()){
                a[i]=c;
                i++;
            }
            i=0;
            for (char ch : t.toCharArray()){
                b[i]=ch;
                i++;
            }
            for (int j = 0; j <t.length() ; j++) {
                if(a[j]!=b[j]){
                    sum++;
                }
            }
            System.out.println(sum);
        }
    }
}
