//BZOJ 1812
 //by Cydiater
 //2016.9.5
 #include <iostream>
 #include <cstdio>
 #include <cstdlib>
 #include <cstring>
 #include <string>
 #include <algorithm>
 #include <queue>
 #include <map>
 #include <ctime>
 #include <cmath>
 #include <iomanip>
 using namespace std;
 #define ll long long
 #define up(i,j,n)        for(int i=j;i<=n;i++)
 #define down(i,j,n)        for(int i=j;i>=n;i--)
 ;
 const int oo=0x3f3f3f3f;
 inline int read(){
     ,f=;
     ;ch=getchar();}
     +ch-';ch=getchar();}
     return x*f;
 }
 ,fa[MAXN],f[MAXN][MAXN][MAXN],pre_fa[MAXN];
 struct edge{
     int y,next,v;
 }e[MAXN<<];
 namespace solution{
     inline void insert(int x,int y,int v){e[++len].next=LINK[x];LINK[x]=len;e[len].y=y;e[len].v=v;}
     void dfs(int node){
         for(int i=LINK[node];i;i=e[i].next){
             dis[e[i].y]=dis[node]+e[i].v;
             dfs(e[i].y);
         }
     }
     void init(){
         N=read();K=read();
         pre_fa[]=-;
         up(i,,N){
             Value[i]=read();int y=read(),v=read();
             pre_fa[i]=y;
             insert(y,i,v);
         }
         dfs();dis[]=;
     }
     void build(int node,int father){
         int tmp=LINK[node];son[node]=e[tmp].y;fa[node]=father;
         if(tmp)build(e[tmp].y,node);node=e[tmp].y;
         for(int i=e[tmp].next;i;i=e[i].next){
             bro[node]=e[i].y;build(e[i].y,node);
             node=e[i].y;
         }
     }
     void TreeDP(int node){
         if(son[node])TreeDP(son[node]);
         if(bro[node])TreeDP(bro[node]);
         int father=pre_fa[node];
         ){
             up(lim,,K)up(k,,lim){
                 int tmp=Value[node]*(dis[node]-dis[father]);
                 if(son[node])tmp+=f[son[node]][father][k];
                 if(bro[node])tmp+=f[bro[node]][father][lim-k];
                 f[node][father][lim]=min(f[node][father][lim],tmp);
             }
             up(lim,,K)up(k,,lim){
                 ;
                 ];
                 if(bro[node])tmp+=f[bro[node]][father][lim-k];
                 f[node][father][lim]=min(f[node][father][lim],tmp);
             }
             father=pre_fa[father];
         }
         ){
             father=;
             up(lim,,K)up(k,,lim){
                 ;
                 if(son[node])tmp+=f[son[node]][father][k];
                 if(bro[node])tmp+=f[bro[node]][father][lim-k];
                 f[node][father][lim]=min(f[node][father][lim],tmp);
             }
         }
     }
     void slove(){
         build(,-);
         memset(f,0x3f,sizeof(f));
         TreeDP();
         printf(][][K]);
     }
 }
 int main(){
     //freopen("input.in","r",stdin);
     using namespace solution;
     init();
     slove();
     ;
 }