#include <bits/stdc++.h>
using namespace std;

int main() {
    int n;
    cin >> n;
    vector<int> parent(n+1), cap(n+1), start(n+1), DP(n+1);
    cin >> cap[0];
    for(int c1 = 0; c1 < n; c1++){
        cin >> parent[c1+1] >> cap[c1+1] >> start[c1+1];
    }
    DP[0] = cap[0];
    int ans = DP[0];
    for(int c1 = 1; c1 <= n; c1++){
        DP[c1] = cap[c1]-start[c1] + max(DP[parent[c1]]-cap[c1],0);
        ans = min(ans, DP[c1]);
    }
    cout << ans << "\n";
    return 0;
}