def calc(S, v, w):
    T = sorted(S[:] + [(min(s[0] + v, V), s[1] + w) for s in S], key = lambda x: -x[0])
    U = []
    prew = 1 << 100
    prev = 1 << 100
    for t in T:
        if t[1] < prew:
            if t[0] == prev:
                U.pop()
            U.append(t)
            prew = t[1]
            prev = t[0]
    return U

N, V, L = map(int, input().split())
S = [(V, 0)]
prex = 0
for _ in range(N):
    x, v, w = map(int, input().split())
    dx = x - prex
    prex = x
    S = [(v - dx, w) for v, w in S if v >= dx]
    S = calc(S, v, w)

dx = L - prex
A = [w for v, w in S if v >= dx]
print(min(A) if A else -1)