A person creates an apparatus as shown in the figure to exercise the extensor muscle of the hand. It is given that OP = 0.15 m, OQ = 0.35 m, θ = 30°, the weight of the lower arm = 20 N, the center of mass of the lower arm is at point P, the magnitude of the applied tensile force F = 50 N. If the extensor muscle is acting with a moment arm of 0.25 m, the muscle force required to hold the hand at the position shown in the figure is ______ N. Give your answer rounded off to the nearest integer.