Magnetic Field with 3 conductors

Three infinitely long thin conductors are joined at the origin of coordinates and lies along the , y and z-axes. A current i flowing along the conductor lying along the negative x-axis divides equally into the other two at origin. The magnitude of magnetic field at the point (0,-a,0) is expressed as $\frac { { \sqrt { \alpha } }{ { \mu }_{ \circ } }{ i } }{ { \beta }{ { \pi }{ a } } }$ then value of ${ \alpha + }{ \beta }$ is ?