If $A+B+C=\pi$ , then the value of  $\frac{\cos A}{\sin B\sin C}+\frac{\cos B}{\sin A\sin C}+\frac{\cos C}{\sin A\sin B}$  is ____

$\sin 2A+\sin 2B+\sin 2C=4\sin A.\sin B.\sin C$

$\frac{\cos A}{\sin B.\sin C}+\frac{\cos B}{\sin C.\sin A}+\frac{\cos C}{\sin A.\sin B}=\frac{2\left(\cos A.\sin A+\cos B\sin B+\cos C\sin C\right)}{2\left(\sin A.\sin B.\sin C\right)}$

$\sin 2\theta =2\sin \theta .\cos \theta$

$=\frac{\sin 2A+\sin 2B+\sin 2C}{2\left(\sin A.\sin B.\sin C\right)}$

$=\frac{4\sin A.\sin B.\sin C}{2\sin A.\sin B.\sin C}=2$