# Problem Definition

## Description

Given an array of N integers, find the pair of integers in the array which have minimum XOR value. Report the minimum XOR value.

Examples:

**Input:** 0 2 5 7

**Output:** 2 (0 XOR 2)

**Input:** 0 4 7 9

**Output:** 3 (4 XOR 7)

**Constraints:** 2 <= N <= 100 000, 0 <= A[i] <= 1 000 000 000

## Notes