#include <bits/stdc++.h>
using namespace std;
#define endl "\n"
#define mod 1000000007
int dp[200001][501],leafs[200001],n,m,arr[200001],rt;
vector <array<int,2>> v[200001];
void build(int i){
if(v[i].size()==0){
leafs[i]=1;
return;
}
for(auto [j,c]:v[i]){
build(j);
leafs[i]+=leafs[j];
}
return;
}
void calc(int i){
for(int k=0;k<=m;k++) dp[i][k]=-1e9;
dp[i][1]=arr[i];
dp[i][0]=0;
for(auto [j,lef]:v[i]){
calc(j);
for(int k=0;k<=leafs[i];k++){
for(int p=0;p<=min(k,leafs[j]);p++){
dp[i][k]=dp[i][k-p]+dp[j][p];
if(dp[i][k]<0) dp[i][k]=-1e9;
}
}
}
return;
}
signed main(){
ios_base::sync_with_stdio(false);
cin.tie(NULL);
cout.tie(NULL);
cin>>n>>m;
for(int i=1;i<n;i++){
int p;
cin>>p>>arr[i];
if(p==0) rt=i;
else v[p].push_back({i,0});
}
build(rt);
for(int i=1;i<=n;i++){
for(int j=0;j<v[i].size();j++) v[i][j][1]=leafs[v[i][j][0]];
sort(v[i].begin(),v[i].end());
}
calc(rt);
cout<<dp[rt][m]<<endl;
}
