#include<bits/stdc++.h>
using namespace std;
int main(void) {
    int n, k;
    scanf("%d%d", &n, &k);
    vector<int> x(n+1, k);
    int ans = k;
    vector<int> tot_above(n+1, 0);
    for (int i = 1; i <= n; ++i) {
        int d, m, c;
        scanf("%d%d%d", &d, &m, &c);
        tot_above[i] = c + tot_above[d];
        x[i] = max(m-c + max(0, x[d]-m), k-tot_above[i]);
        ans = min(ans, x[i]);
    }
    printf("%d\n", ans);
}