import java.util.*;

class Main{
	
	public static void main(String args[]){

		Scanner src = new Scanner(System.in);

		String s = src.nextLine();
      	String t = src.nextLine();
      
      	

		System.out.println(solve(s,t));
	}

  	public static int solve(String s,String t){
      
      int ans = 0;
      
      int i =0;
      int j = 0;
      
      while(i<s.length() && j<t.length()){
        
        if(s.charAt(i)!=t.charAt(j))
          ans++;
        
        i++;
        j++;
        
      }
      
      return ans;
      
    }

} import java.util.*; util.* java class Main{
	
	public static void main(String args[]){

		Scanner src = new Scanner(System.in);

		String s = src.nextLine();
      	String t = src.nextLine();
      
      	

		System.out.println(solve(s,t));
	}

  	public static int solve(String s,String t){
      
      int ans = 0;
      
      int i =0;
      int j = 0;
      
      while(i<s.length() && j<t.length()){
        
        if(s.charAt(i)!=t.charAt(j))
          ans++;
        
        i++;
        j++;
        
      }
      
      return ans;
      
    }

} Main public static void main(String args[]){

		Scanner src = new Scanner(System.in);

		String s = src.nextLine();
      	String t = src.nextLine();
      
      	

		System.out.println(solve(s,t));
	} main {

		Scanner src = new Scanner(System.in);

		String s = src.nextLine();
      	String t = src.nextLine();
      
      	

		System.out.println(solve(s,t));
	} Scanner src = new Scanner(System.in); src new Scanner(System.in) String s = src.nextLine(); s src.nextLine() src.nextLine src String t = src.nextLine(); t src.nextLine() src.nextLine src System.out.println(solve(s,t)) System.out.println System.out System System.out solve(s,t) solve s t String args[] args public static int solve(String s,String t){
      
      int ans = 0;
      
      int i =0;
      int j = 0;
      
      while(i<s.length() && j<t.length()){
        
        if(s.charAt(i)!=t.charAt(j))
          ans++;
        
        i++;
        j++;
        
      }
      
      return ans;
      
    } solve {
      
      int ans = 0;
      
      int i =0;
      int j = 0;
      
      while(i<s.length() && j<t.length()){
        
        if(s.charAt(i)!=t.charAt(j))
          ans++;
        
        i++;
        j++;
        
      }
      
      return ans;
      
    } int ans = 0; ans 0 int i =0; i 0 int j = 0; j 0 while(i<s.length() && j<t.length()){
        
        if(s.charAt(i)!=t.charAt(j))
          ans++;
        
        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))
          ans++;
        
        i++;
        j++;
        
      } if(s.charAt(i)!=t.charAt(j))
          ans++; s.charAt(i)!=t.charAt(j) s.charAt(i) s.charAt s i t.charAt(j) t.charAt t j ans++ ans i++ i j++ j return ans; ans String s s String t t
import java.util.*;

class Main{
	
	public static void main(String args[]){

		Scanner src = new Scanner(System.in);

		String s = src.nextLine();
      	String t = src.nextLine();
      
      	

		System.out.println(solve(s,t));
	}

  	public static int solve(String s,String t){
      
      int ans = 0;
      
      int i =0;
      int j = 0;
      
      while(i<s.length() && j<t.length()){
        
        if(s.charAt(i)!=t.charAt(j))
          ans++;
        
        i++;
        j++;
        
      }
      
      return ans;
      
    }

}