// https://judge.yosupo.jp/problem/range_chmin_chmax_add_range_sum
#include <bits/stdc++.h>
using namespace std;
const int N = 2e5 + 3, M = 500 + 3;
int n, m, a[N];
vector<int> g[N];
int id, in[N], out[N];
vector<int> lst[N];
int f[N][M];
void dfs(int u) {
in[u] = ++id;
for (int v: g[u]) dfs(v);
out[u] = id;
lst[id].push_back(u);
}
void solve() {
cin >> n >> m;
for (int i = 1; i <= n; ++i) {
int p; cin >> p >> a[i];
g[p].push_back(i);
}
dfs(g[0][0]);
for (int i = 1; i <= m; ++i) f[0][i] = -1e9;
for (int i = 1; i <= n; ++i) {
for (int j = 1; j <= m; ++j) {
f[i][j] = f[i - 1][j];
for (int x: lst[i]) f[i][j] = max(f[i][j], f[in[x] - 1][j - 1] + a[x]);
}
}
cout << f[n][m];
}
int main() {
ios_base::sync_with_stdio(false);
cin.tie(NULL);
solve();
return 0;
}
