class Node:
    def __init__(self, val, left, right):
        self.val = val
        self.left = left
        self.right = right

class Solution:
    def __init__(self, root):
        self.root = root
        self.level = 0
        self.mas = []

    def sum(self, root, level):
        try:
            self.mas[level] += root.val
        except:
            self.mas.append(root.val)
        if root.left is not None:
            self.sum(root.left, level + 1)
        if root.right is not None:
            self.sum(root.right, level + 1)

    def answer(self):
        ans = [0] * len(self.mas)
        ans[0] = self.mas[0]
        for i in range(1, len(ans)):
            ans[i] = ans[i - 1] + self.mas[i]
        return ans