Usb1 Usb2,Usb3
Usb2 val1,val2,Usb4
Usb3 val3
Usb4 val4


##</code><code>##

Input : Usb1 

print Usb2[val1,val2,Usb4[val4]],Usb3[val3]

Input : Usb2

print val1,val2,Usb4[val4]