IR-MO-R2 2018 Problem 1

Let $P$ be the intersection of $AC$ and $BD$ in isosceles trapezoid $ABCD$ ( $AB\parallel CD$ , $BC=AD$ ) . The circumcircle of triangle $ABP$ inersects $BC$ for the second time at $X$ . Point $Y$ lies on $AX$ such that $DY\parallel BC$ . Prove that $\hat {YDA} =2.\hat {YCA}$ .