text: int findCeil(TreeNode* root , int key){
    int ceili = -1;
    while(root){
      if(root->val == key){
        ceili = root->data;
        return ceili;
      }
      if(key > root->val){
        root = root->right;
      }
      else{
        ceili = root->val;
        root = root->left;
      }
    }
    return ceili;
  }
  