class Solution:

    def sumRootToLeaf(self, root: TreeNode) -> int:

        stack=[(root,0)]

        ans=[]

        bi_str=[]

        while stack:

            node,level=stack.pop()

            s_len=len(bi_str)

            if s_len-1<level:

                bi_str.append(str(node.val))

            else:

                bi_str[level]=str(node.val)

                del bi_str[level+1:]

            if (not node.left) and (not node.right):

                ans.append(int(''.join(bi_str),2))

            if node.right:

                stack.append((node.right,level+1))

            if node.left:

                stack.append((node.left,level+1))

        return sum(ans)