Let S1 and S2 be two spheres with distinct radii that touch externally. The spheres lie inside a cone C, and each sphere touches the cone in a full circle. Inside the cone there are n additional solid spheres arranged in a ring in such a way that each solid sphere touches the cone C, both of the spheres S1 and S2 externally, as well as the two neighboring solid spheres. What are the possible values of n?Proposed by Iceland. geometry3D geometryspheretrigonometryfunctionIMO Shortlist