The real power drawn by a balanced load connected to a $\text{400 V, 50 Hz,}$ balanced, symmetrical 3-phase, 3-wire, $RYB$ sequence mains is measured using the two-wattmeter method. Wattmeter $W_1$ is connected in the $R$ line and wattmeter $W_2$ is connected in the $B$ line. The line current is measured as $\frac{1}{\sqrt3}A$. If the wattmeter $W_1$ reads zero, the reading on $W_2$ (in watts) is _______.