while stack:
    node = stack.pop()
    if node.left:
        stack.append(node.left)
    result.append(node.val)

const memo = new Map();
function dp(i, j) {
  const key = `${i},${j}`;
  if (memo.has(key)) return memo.get(key);
  const res = dp(i-1,j) + dp(i,j-1);
  memo.set(key, res); return res;
}

sort(v.begin(), v.end(),
  [](auto& a, auto& b){
    return a.second < b.second;
  });
int ans = 0;
for (auto& [l, r] : v)
  if (l >= ans) ans = r;

Graph g(n);
for (auto& [u, v] : edges)
  g.addEdge(u, v);
vector<int> dist = g.bfs(0);

def sieve(n):
    primes = [True] * (n+1)
    p = 2
    while p*p <= n:
        if primes[p]:
            for i in range(p*p, n+1, p):
                primes[i] = False
        p += 1
    return primes