#include <bits/stdc++.h>
using namespace std;
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace __gnu_pbds;
#define ordered_set tree<ll, null_type,less<ll>, rb_tree_tag,tree_order_statistics_node_update>
#define endl '\n'
using ll = long long;
#define pb push_back
#define pF first
#define pS second
#define SP <<' '<<
const ll mod = 998244353;
ll dp[212345][600], a[212345], sz[212345];
vector<ll> v[212345];
ll m;
void dfs(ll i, ll p) {
dp[i][0] = 0;
for (auto j : v[i]) {
if (j != p) dfs(j, i);
for (int k = m; k >= 0; k--) {
for (int k1 = 0; k1 <= k; k1++) {
dp[i][k] = max(dp[i][k], dp[i][k1] + dp[j][abs(k-k1)]);
}
}
}
dp[i][1] = max(dp[i][1], a[i]);
}
int main() {
ios::sync_with_stdio(false);cin.tie(nullptr);cout.tie(nullptr);
ll n; cin>>n>>m;
for (int i=1; i<=n; i++) for (int j = 0; j<=m; j++) dp[i][j] = -INT_MAX;
ll root;
for (int i=1; i<=n; i++) {
ll p, x;
cin>>p>>x;
v[p].pb(i);
a[i] = x;
if (p == 0) root = i;
}
dfs(root, 0);
cout << dp[root][m];
}
