n this exercise, you will create a circuit with two levels of hierarchy. Your top$\_$module will instantiate two copies of add$16($provided$),$ each of which will instantiate $16$ copies of add$1($which you must write$).$ Thus, you must write two modules: top$\_$module and add$1.$

Like module$\_$add, you are given a module add$16$ that performs a $16-$bit addition. You must instantiate two of them to create a $32-$bit adder. One add$16$ module computes the lower $16$ bits of the addition result, while the second add$16$ module computes the upper $16$ bits of the result. Your $32-$bit adder does not need to handle carry$-$in $($assume $0)$ or carry$-$out $($ignored$).$

Connect the add$16$ modules together as shown in the diagram below. The provided module add$16$ has the following declaration:

module add$16($ input$[15$:$0]$ a$,$ input$[15$:$0]$ b$,$ input cin, output$[15$:$0]$ sum, output cout $)$;

Within each add$16,16$ full adders $($module add$1,$ not provided$)$ are instantiated to actually perform the addition. You must write the full adder module that has the following declaration:

module add$1($ input a$,$ input b$,$ input cin, output sum, output cout $)$;

Recall that a full adder computes the sum and carry$-$out of a$+$b$+$cin.

In summary, there are three modules in this design:

top$\_$module $$ Your top$-$level module that contains two of$...$

add$16,$ provided $$ A $16-$bit adder module that is composed of $16$ of$...$

add$1$ A $1-$bit full adder module.