The resultant of the two vectors $\overrightarrow{A}$ and $\overrightarrow{B}$ is perpendicular to the vector $\overrightarrow{A}$ and its magnitude is equal to half of the magnitude of vector $\overrightarrow{B}$. Then the angle between $\overrightarrow{A}$and $\overrightarrow{B}$ is__________