#include <bits/stdc++.h>
using namespace std;
#define ll long long
int main() {
ios::sync_with_stdio(0);
cin.tie(0);
int n, m;
cin >> n >> m;
vector<vector<int>> g(n);
vector<int> p(n, -1), x(n);
for (int i = 0; i < n; i++) {
cin >> p[i] >> x[i];
--p[i];
if (p[i] >= 0) g[p[i]].push_back(i);
}
vector<int> tin(n), tout(n), vertex(n);
int timer = 0;
auto dfs = [&](auto self, int v) -> void {
tin[v] = timer++;
vertex[tin[v]] = v;
for (int u : g[v]) self(self, u);
tout[v] = timer;
};
for (int i = 0; i < n; i++) if (p[i] == -1) dfs(dfs, i);
vector<vector<int>> dp(n + 1, vector<int>(m + 1, -1e9));
dp[n][0] = 0;
for (int i = n - 1; i >= 0; --i)
for (int j = m; j >= 0; --j) {
int v = vertex[i];
dp[i][j] = dp[i + 1][j];
if (j >= 1) dp[i][j] = max(dp[i][j], dp[tout[v]][j - 1] + x[v]);
}
cout << dp[0][m] << "\n";
}
