Suppose two binary trees, T₁ and T₂, hold entries satisfying the heap-order property (but not necessarily the complete binary tree property). Describe a method for combining T₁ and T₂ into a binary tree T, whose nodes hold the union of the entries in T₁ and T₂ and also satisfy the heap-order property. Your algorithm should run in time O(h₁ +h₂) where h₁ and h₂ are the respective heights of T₁ and T₂.