
import java.util.*;
 public class Main {
    public static void main(String[] args) {
        Scanner sc = new  Scanner(System.in);
      String s = sc.next();
      String t = sc.next();
      int count =0;
      for(int i=0;i<s.length();i++){
         outer: for(int j =i;j<s.length();j++){
              if(s.charAt(i)!=t.charAt(j)){
                  count++;
               break outer;
              }else{
                  break outer;
              }
          }
      }
      System.out.println(count);
        
    


}

    }
    

/tmp/hf-datasets-cache/medium/datasets/42704881117311-config-parquet-and-info-qiankunmu-Project_CodeNet-896c9d36/hub/datasets--qiankunmu--Project_CodeNet_Python800_and_Java250/snapshots/c899fde44a77ba1cc14973ed3de064e4ff3aadc7/Project_CodeNet_Java250.tar.gz