System.out.println(1 << 0);//1
System.out.println(1 << 1);//2
System.out.println(1 << 2);//4
System.out.println(1 << 3);//8
System.out.println(1 << 4);//16
System.out.println(1 << 0);//1
System.out.println(1 << 1);//2
System.out.println(1 << 2);//4
System.out.println(1 << 3);//8
System.out.println(1 << 4);//16