Solution Review: Finding Minimum Value in a Binary Search Tree

using System;
namespace chapter_6
{
    class Solution
    {
        static public int findMin(Node rootNode)
        {
            // Traverse (in order) towards left till you reach leaf node,
            //and then return leaf node's value
            if (rootNode == null)
                return -1;
            while (rootNode.leftChild != null)
            {
                rootNode = rootNode.leftChild;
            }
            return rootNode.value;
        }
        static void Main(string[] args)
        {
            BinarySearchTree bsT = new BinarySearchTree(6);
            bsT.insertBST(3);
            bsT.insertBST(8);
            bsT.insertBST(12);
            bsT.insertBST(10);
            bsT.insertBST(14);
           Console.WriteLine(findMin(bsT.getRoot()));
            return;
        }
    }
}