if !ENV['RUBY_THREAD_VM_STACK_SIZE']
  exec({'RUBY_THREAD_VM_STACK_SIZE'=>'100000000'}, '/usr/bin/ruby', $0)
else
  N, Q = gets.split.map(&:to_i)
  E = Hash.new { |h, k| h[k] = [] }

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

  C = Array.new(N + 1, 0)

  def dfs(v, visited)
    cnt = 1
    visited[v] = true

    E[v].each do |u|
      next if visited[u]

      cnt += dfs(u, visited)
    end

    C[v] = cnt
  end

  visited = Array.new(N + 1, false)
  dfs(1, visited)
  ans = 0

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

    puts ans
  end
end