How many $m-$ input NAND gates are needed to construct a $n-$ input NAND gate, where $m \leq n$
Examples:
> constructing $3-$input NAND gate using $2-$input NAND gate
> constructing $4-$input NAND gate using $2-$input NAND gate
> constructing $4-$input NAND gate using $4-$input NAND gate
Is there a general solution to this problem, or is there NO general solution available (i.e., a localized solution may exist)?