[ The sum of the angles of a triangle. The theorem about the exterior angle. ]

[ Criteria and properties of an isosceles triangle. ]

Given an isosceles triangle $A B C(A B=A C)$. On the extension of side $A C$ beyond point $C$, segment $C D$ is laid out, equal to $B C$. It turns out that $B D=A B$.

Find the angles of triangle $A B C$.