MathNet 2018-part-01 — 181 problems (EN–VI) Question 170

The points $D$ and $E$ divide side $AB$ of the equilateral triangle $ABC$ into three equal parts, with $D$ between $A$ and $E$. The point $F$ lies on side $BC$ so that $CF = AD$. Find the sum of the angles $\angle CDF + \angle CEF$.