G. Xor-MST
time limit per test
2 seconds
memory limit per test
256 megabytes
input
standard input
output
standard output

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

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

Print one number — the weight of the minimum spanning tree in the graph.

Examples
Input
5
1 2 3 4 5
Output
8
Input
4
1 2 3 4
Output
8