import java.io.BufferedReader;
        import java.io.IOException;
        import java.io.InputStreamReader;
        import java.nio.charset.StandardCharsets;
        import java.util.stream.IntStream;

public class Main{
    public static void main(String args[]) throws IOException {
        InputStreamReader reader = new InputStreamReader(System.in, StandardCharsets.UTF_8);
        BufferedReader in = new BufferedReader(reader);
        String line;
        String input = "";
        while ((line = in.readLine()) != null) {
            input = line;
        }
        String[] parts = input.split(" ");
        int node1 = Integer.parseInt(parts[0]);
        int node2 = Integer.parseInt(parts[1]);

        int[] node_vals = new int[]{30,8,52,3,20,10,29};
        if(IntStream.of(node_vals).noneMatch(x -> x == node1)){
            System.out.print("Value "+  node1  + " does not exist in a tree");
        }
        if(IntStream.of(node_vals).noneMatch(x -> x == node2)){
            System.out.print("Value "+  node2  + " does not exist in a tree");
        }

        BinaryTree tree = new BinaryTree();
        tree.root = new Node(30);
        tree.root.left = new Node(8);
        tree.root.right = new Node(52);
        tree.root.left.left = new Node(3);
        tree.root.left.right = new Node(20);
        tree.root.left.right.left = new Node(10);
        tree.root.left.right.right = new Node(29);

        Node t = tree.lca(tree.root, node1, node2);
        System.out.println(t.data);
    }
}

class Node {
    int data;
    Node left, right;

    Node(int item) {
        data = item;
        left = right = null;
    }
}

class BinaryTree {
    Node root;

    Node lca(Node node, int n1, int n2) {
        if (node == null)
            return null;

        // If both n1 and n2 are smaller than root, then LCA lies in left
        if (node.data > n1 && node.data > n2)
            return lca(node.left, n1, n2);

        // If both n1 and n2 are greater than root, then LCA lies in right
        if (node.data < n1 && node.data < n2)
            return lca(node.right, n1, n2);

        return node;
    }
}