Python code

Complete the preOrder function in the editor below, which has $1$ parameter: a pointer to the root of a binary tree. It must print the values in the tree's preorder traversal as a single line of space$-$separated values.

Input Format

Our test code passes the root node of a binary tree to the preOrder function.

Constraints

$1<=$Nodes in the tree$<=500$

Output Format

Print the tree's preorder traversal as a single line of space$-$separated values.

Sample Input

$1$

$\backslash$

$2$

$\backslash$

$5$

$/\backslash$

$36$

$\backslash$

$4$

Sample Output

$125346$

Explanation

The preorder traversal of the binary tree is printed.