n = read_line.to_i
c = read_line.to_i
v = read_line.to_i

graph = Array.new(n) { [] of Tuple(Int32, Int32, Int32) }

v.times do
  s, t, y, m = read_line.split.map(&.to_i)
  graph[s - 1] << {t - 1, y, m}
end

INF = 1_000_000_000
dp = Array.new(c + 1, INF)
dp[c] = 0

n.times do |i|
  temp = dp.dup
  edges = graph[i]
  
  c.downto(0) do |k|
    current_time = temp[k]
    next if current_time == INF
    
    edges.each do |to, cost, time|
      next if k < cost
      
      new_k = k - cost
      new_time = current_time + time
      if new_time < dp[new_k]
        dp[new_k] = new_time
      end
    end
  end
end

result = dp.min
puts result == INF ? -1 : result