Atomic Structure

The kinetic energy of electrons emitted, when radiation of frequency $1.0 \times 10^{15} \mathrm{~Hz}$ hits a metal, is $2 \times 10^{-19} \mathrm{~J}$. What is the threshold frequency of the metal (in Hz )? $\left(h=6.6 \times 10^{-34} \mathrm{Js}\right)$