Problem 20 (2018 AMC 8)

In $\triangle ABC$, a point $E$ is on $\overline{AB}$ with $AE=1$ and $EB=2$. Point $D$ is on $\overline{AC}$ so that $\overline{DE}\parallel\overline{BC}$ and point $F$ is on $\overline{BC}$ so that $\overline{EF}\parallel\overline{AC}$. What is the ratio of the area of $CDEF$ to the area of $\triangle ABC$? [See figure in original PDF]