/* package whatever; // don't place package name! */

import java.util.*;
import java.lang.*;
import java.io.*;

/* Name of the class has to be "Main" only if the class is public. */
class Ideone
{
	public static void main (String[] args) throws java.lang.Exception
	{
		Optional<Integer> myOptional = Optional.of(0);
		
		Integer result;
		if (myOptional.isPresent()) {
    		result = myOptional.get() * 2;
		} else {
    		result = 0;
		}
		System.out.println(result);
		
		Integer result2;
		if (myOptional.isPresent()) {
    		result2 = myOptional.get() * 2;
		}
		System.out.println(result2);  // Compiler error.
		
		Integer result3;
		if (!myOptional.isPresent()) {
    		result3 = 0;
		}
		System.out.println(result3);  // Compiler error.
	}
}