A signal is band-limited to $\text{0 to 12 kHz}$. The signal spectrum is corrupted by additive noise which is band-limited to $\text{10 to 12 kHz}$. Theoretically, the minimum rate in kilohertz at which the noisy signal must be sampled so that the $\text{UNCORRUPTED PART}$ of the signal spectrum can be recovered, is _____________ $kHz.$
