/**
 * struct TreeNode {
 *	int val;
 *	struct TreeNode *left;
 *	struct TreeNode *right;
 * };
 */
/**
 * 代码中的类名、方法名、参数名已经指定,请勿修改,直接返回方法规定的值即可
 *
 * 
 * @param root TreeNode类 
 * @param p int整型 
 * @param q int整型 
 * @return int整型
 */
int lowestCommonAncestor(struct TreeNode* root, int p, int q ) {
    // write code here
    if(root == NULL) return 0;
    if(root->val <= p && root->val >= q) return root->val;
    else if(root->val >= p && root->val <= q) return root->val;
    else if(root->val > p && root->val > q) return lowestCommonAncestor(root->left, p, q);
    return lowestCommonAncestor(root->right, p, q);

}