N,S,H=map(int,input().split())
seg=[tuple(map(int,input().split())) for i in range(N)]
dp=[0]*(N+1)
lf=0
for i in range(N):
    if seg[i][1]-seg[i][0]>S:
        continue
    while seg[i][0]-seg[lf][1]>=H:
        lf+=1
    dp[i+1]=max(dp[i],dp[lf]+seg[i][2])
print(dp[-1])