"""
TreeNode* mergeTrees(TreeNode* root1, TreeNode* root2) {
if(root1==NULL and root2==NULL)
return NULL;
if(root1!=NULL and root2==NULL)
return root1;
if(root1==NULL and root2!=NULL)
{
return root2;
}
root1->val=root1->val+root2->val;
root1->left=mergeTrees(root1->left,root2->left);
root2->right=mergeTrees(root1->right,root2->right);
return root1;
}
};

"""