def closestNumbers(arr, n):
    # Write your code here
    sorted_arr = sorted(arr)
    smallest_diff = float('inf')
    diff_arr = []
    for i in range(n - 1):
        first = sorted_arr[i]
        second = sorted_arr[i+1]
        diff = second - first
        if diff < smallest_diff:
            smallest_diff = diff
            diff_arr = [first, second]
        elif diff == smallest_diff:
            diff_arr.append(first)
            diff_arr.append(second)
            
    return diff_arr