N, M = gets.split.map(&:to_i)
J = N.times.map { gets.split.map(&:to_i) }
J.sort_by! { |v, w| -v }

dp = Array.new(N + 1) { Array.new(M + 1, 0) }
ans = 0

J.each_with_index do |(v, w), i|
  M.downto(0) do |j|
    dp[i + 1][j] = dp[i][j]
    nw = j + w
    nv = dp[i][j] + v
    next if nw > M

    if dp[i + 1][nw] < nv
      dp[i + 1][nw] = nv
      ans = nv * v if ans < nv * v
    end
  end
end

puts ans