#region Header
#!/usr/bin/env python3
# from typing import *

import sys
import io
import math
import collections
import decimal
import itertools
from queue import PriorityQueue
import bisect
import heapq

def input():
    return sys.stdin.readline()[:-1]

sys.setrecursionlimit(1000000)
#endregion

# _INPUT = """1 8 9
# 9 4 382593220
# """
# sys.stdin = io.StringIO(_INPUT)



def main():
    N, V, L = map(int, input().split())
    x = [None for _ in range(N)] + [L]
    v = [None for _ in range(N)]
    w = [None for _ in range(N)]
    for i in range(N):
        x[i], v[i], w[i] = map(int, input().split())
        if i == 0 and V - x[0] < 0:
            print(-1)
            return
        elif i >= 1 and x[i] - x[i-1] > V:
            print(-1)
            return
    if L - x[N-1] > V:
            print(-1)
            return

    dp = [[10**10 for _ in range(V+1)] for _ in range(N+1)]
    dp[0][V-x[0]] = 0
    for i in range(N):
        d = x[i+1] - x[i]
        for v in range(V+1):
            if dp[i][v] < 10**10:
                if v-(x[i+1]-x[i]) >= 0:
                    dp[i+1][v-d] = min(dp[i+1][v-d], dp[i][v])
                dp[i+1][V-d] = min(dp[i+1][V-d], dp[i][v] + w[i])

    MinW = min(dp[N])
    if MinW == 10**10:
        print(-1)
    else:
        print(MinW)

if __name__ == '__main__':
    main()