n, k = read_line.split.map(&.to_i)
p, d = (1..n).map { read_line.split.map(&.to_i) }.sort.reverse.transpose
I = -10**9
dp = [{0, I}] + [{I, I}] * k
n.times { |i|
  dp = (0..k).map { |j|
    { {dp[j][0], dp[j][1] + d[i]}.max, {dp[j][1], j >= p[i] ? dp[j - p[i]][0] + d[i] : I}.max }
  }
}
puts dp.max_of(&.max)