Description: You are given a complete undirected graph with n vertices. A number ai is assigned to each vertex, and the weight of an edge between vertices i and j is equal to ai xor aj. Calculate the weight of the minimum spanning tree in this graph. Input Format: The first line contains n (1 ≤ n ≤ 200000) — the number of vertices in the graph. The second line contains n integers a1, a2, ..., an (0 ≤ ai < 230) — the numbers assigned to the vertices. Output Format: Print one number — the weight of the minimum spanning tree in the graph. Note: None