Please reason step by step, and put your final answer within \boxed{}.
Given an acute-angled triangle \(ABC\). A line parallel to \(BC\) intersects sides \(AB\) and \(AC\) at points \(M\) and \(P\) respectively. For which positions of points \(M\) and \(P\) will the radius of the circumcircle of triangle \(BMP\) be the smallest?
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