#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <cmath>
#include <algorithm>
#include <assert.h>
#define IOS ios::sync_with_stdio(false)
using namespace std;
#define inf (0x3f3f3f3f)
typedef long long int LL;


#include <iostream>
#include <sstream>
#include <vector>
#include <set>
#include <map>
#include <queue>
#include <string>
#include <bitset>
const int maxn = 1e2 + 20;
int Lchild[maxn], Rchild[maxn], dp[maxn][maxn][maxn];
int a[maxn], fa[maxn], len[maxn];
int dfs(int cur, int hasPoint, int k, int dis) {
    if (cur == -1 || hasPoint == -1) return 0;
    if (dp[cur][hasPoint][k] != inf) return dp[cur][hasPoint][k];
    int &now = dp[cur][hasPoint][k]; //引用改值
    for (int i = 0; i <= k; ++i) { //这个cur节点不做中转站。
        now = min(now, dfs(Lchild[cur], hasPoint, i, dis + len[cur]) + dfs(Rchild[cur], hasPoint, k - i, dis) + a[cur] * (dis + len[cur]));
    }
    for (int i = 0; i < k; ++i) { // 这个点用来中转
        now = min(now, dfs(Lchild[cur], cur, i, 0) + dfs(Rchild[cur], hasPoint, k - i - 1, dis));
    }
    return dp[cur][hasPoint][k];
}
void work() {
    int n, k;
    cin >> n >> k;
    memset(dp, 0x3f, sizeof dp);
    memset(Lchild, -1, sizeof Lchild);
    memset(Rchild, -1, sizeof Rchild);
    for (int i = 1; i <= n; ++i) {
        cin >> a[i] >> fa[i] >> len[i];
        Rchild[i] = Lchild[fa[i]];
        Lchild[fa[i]] = i;
    }
    cout << dfs(0, 0, k, 0) << endl;
}

int main() {
#ifdef local
    freopen("data.txt", "r", stdin);
//    freopen("data.txt", "w", stdout);
#endif
    work();
    return 0;
}