data class Node(
    var left: Node?,
    var right: Node?,
    var data: Int
)

fun placeNode(head: Node, new: Node) {
    // left
    if(head.data > new.data) {
       if(head.left == null) {
           // println("Place Left " + new.data)
            head.left = new
       } else {
            placeNode(head.left!!, new)
       }
    }
    
    // right
    if(head.data < new.data) {
        if(head.right == null) {
            //println("Place Right " + new.data)
            head.right = new
        } else {
            placeNode(head.right!!, new)
        }
    }
}

fun makeBinaryTree(ints: List<Int>): Node? {
    if(ints.size < 1) return null
    
    val root = Node(null, null, ints[0])
    
    for(i in 1..ints.size-1) {
        val node = Node(null, null, ints[i])
        
        placeNode(root, node)
    }
    return root
}

fun main(args: Array<String>) {
        /* Enter your code here. Read input from STDIN. Print output to STDOUT. */

    val scan = Scanner(System.`in`)

    val nodeCount = scan.nextLine().trim().toInt()
    val item = scan.nextLine()
    val items = item.split(" ").map { it.toInt()}
    //println(items.joinToString())
    val value = scan.nextLine()
    val values = value.split(" ")
    //println(values.joinToString())
    val v1 = values[0].toInt()
    val v2 = values[1].toInt()
    

    val root = makeBinaryTree(items)
    println(findLowestCommonAncestor(v1, v2, root!!))

}