class Solution {

public:

    void helper(TreeNode* node, int& idx, int k, int& res){

        if(res!=INT_MAX)

            return;

        if(!node)

            return;

        //a(node)

        //lk("root",node)

        //dsp

        helper(node->left, idx, k, res);

        if(idx==k){

            res=node->val;

            //dsp

        }

        ++idx;

        helper(node->right, idx, k, res);

    }

    int kthSmallest(TreeNode* root, int k) {

        int idx=;

        int res=INT_MAX;

        //ahd(root)

        //a(res)

        //a(k)

        //a(idx)

        helper(root, idx, k, res);

        return res;

    }

};