The point $E$ is taken inside the square $ABCD$, the point $F$ is taken outside, so that the triangles $ABE$ and $BCF$ are congruent . Find the angles of the triangle $ABE$, if it is known that$EF$ is equal to the side of the square, and the angle $BFD$ is right.
Problem
Source: Sharygin 2006 VIII-X CR 7
Tags: geometry, square, Angle Chasing, congruent triangles