Trees-Sum of all nodes

Given a generic tree, count and return the sum of all nodes present in the given tree.
Input format :
Elements in level order form separated by space (as per done in class). Order is - 
Root_data, n (No_Of_Child_Of_Root), n children, and so on for every element 
Output Format :
Sum of all nodes
Sample Input :
10 3 20 30 40 2 40 50 0 0 0 0 
Sample Output :
190

*************************Solution*************************

public static int sumOfAllNode(TreeNode<Integer> root){
		
		if(root==null)
			return 0;
      
		int sum=0;
		for(int i=0; i<root.children.size();i++)
		{
			sum= sum+sumOfAllNode(root.children.get(i));
		}
		return root.data+sum;
	}