#!/usr/bin/env python3
(n, k) = map(int, input().split())
x = [k]*(n+1)
ans = k
v = 0
for i in range(1, n+1):
    (d, m, c) = map(int, input().split())
    x[i] = m-c + max(0, x[d]-m)
    if c >= v:
        v = c
        ans = min(ans, x[i])
print(ans)