N, A, B = map(int, input().split())
XYK = [tuple(map(int, input().split())) for i in range(N)]
dp = {(1 << i, -1, i)for i in range(N)}
# print(dp)
for k in range(1, N):
    dp_ = set()
    for b, s, t in dp:
        for j in range(N):
            if (1 << j) & b > 0:
                continue
            if abs(XYK[t][2]-XYK[j][2]) >= B:
                dp_.add(((1 << j) | b, t, j))
                continue
            if abs(XYK[j][0]-XYK[t][0])+abs(XYK[j][1]-XYK[t][1]) >= A:
                dp_.add(((1 << j) | b, t, j))
                continue
            if s != -1 and abs(XYK[j][0]-XYK[t][0])+abs(XYK[j][1]-XYK[t][1])+abs(XYK[j][0]-XYK[s][0])+abs(XYK[j][1]-XYK[s][1]) >= A:
                dp_.add(((1 << j) | b, t, j))
    dp = dp_
    # print(dp)
    if dp:
        continue
    print(k)
    break
else:
    print(N)