## https://yukicoder.me/problems/no/3424

import heapq

def main():
    N, T = map(int, input().split())
    l_map = {}
    max_r = 0
    for _ in range(N):
        l, r, p = map(int, input().split())
        if l not in l_map:
            l_map[l] = []
        l_map[l].append((r, p))
        max_r = max(max_r, r)
    max_r += 1

    queue = []
    dp = [0] * (max_r + 1)
    cum_dp = [0] * (max_r + 1)
    for t in range(max_r + 1):
        if t in l_map:
            for r, p in l_map[t]:
                heapq.heappush(queue, (-p, r))        

        while len(queue) > 0 and queue[0][1] < t:
            heapq.heappop(queue)
            
        if len(queue) > 0:
            p0, _  = queue[0]
            p0 = -p0
            dp[t] = p0
            if t - T >= 0:
                dp[t] = max(dp[t], cum_dp[t - T] + p0)
            
        cum_dp[t] = max(cum_dp[t - 1], dp[t])

    answer = cum_dp[-1]
    print(answer)






    



if __name__ == "__main__":
    main()