MS is empty initailly, and operations are in three types, which are as follows:
Given a multiset {MS} MS and {q} q operations. {MS} MS is empty initailly, and operations are in three types, which are as follows: 1. insert an element {x} x into {MS} MS 2. erase an element {x} x from {MS} MS 3. given an integer {x} x, determine whether you can choose two elements {a, b} a,b in {MS} MS that three segments of length {a, b, x} a,b,x can make a nondegenerate triangle.
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