Want to print serial number on smartform

Hi Guys,

I want to develop a smart form, where I need to print a serial number on it.

my requirement is,

If form is printed twice the serial number on first form will be 1 and on the next form will be 2 and continues every time it printed. it means the next time it printed will take serial number 3 and so on.

it is like label printing, if one order contains 2 labels in it. the label should print twice each carrying different serial number 1 & 2, and the next order printed should take sequence from last printed sequence number i.e., 3 & 4 and so on.

please provide your ideas how could I implement this one.

Thanks in Advance.

Nb M