require 'tsort'

class Hash
  include TSort
  alias tsort_each_node each_key
  def tsort_each_child(node, &block)
    fetch(node).each(&block)
  end
end

N, Q = gets.split.map(&:to_i)
E = Hash.new
RE = Hash.new { |h, k| h[k] = [] }
1.upto(N) do |v|
  E[v] = []
end

(N - 1).times do
  a, b = gets.split.map(&:to_i)
  E[a] << b
  RE[b] << a
end

C = Array.new(N + 1, 0)
E.tsort.each do |v|
  C[v] += 1

  RE[v].each do |u|
    C[u] += C[v]
  end
end

ans = 0

Q.times do
  p, x = gets.split.map(&:to_i)
  ans += C[p] * x

  puts ans
end