import java.util.regex.Matcher;
import java.util.regex.Pattern;
import java.util.*;

public class HelloWorld{


     public static void main(String []args){
         String line = "7*8";
         String pattern = "[0-9]+|[*/+-]";
        System.out.println("Hello World");
        Pattern r = Pattern.compile(pattern);

      // Now create matcher object.
      Matcher m = r.matcher(line);
      List<String> output = new ArrayList<String>();
      while(m.find()) {
         output.add(m.group());
      }
      String a[] = output.toArray(new String[0]);
      switch(a[1]){
          case "*":
              System.out.println(Integer.parseInt(a[0])*Integer.parseInt(a[2]));
      }
     }
}