#include <bits/stdc++.h>
using namespace std;
const int NM = 2e5, MM = 500, inf = 1e9+7;
int N, M, root, p[NM+5], x[NM+5], timer = 0, tin[NM+5], tout[NM+5], tour[NM+5];
vector <int> son[NM+5];
int dp[NM+5][MM+5], ans = 0;
void dfs_euler_tour(int u){
tin[u] = ++timer;
tour[timer] = u;
for (int v : son[u]){
dfs_euler_tour(v);
}
tout[u] = timer;
}
int main(){
ios_base::sync_with_stdio(0);
cin.tie(0);
cout.tie(0);
cin >> N >> M;
for (int i = 1; i <= N; i++){
cin >> p[i] >> x[i];
if (p[i] == 0) root = i;
son[p[i]].push_back(i);
}
dfs_euler_tour(root);
for (int i = 1; i <= M; i++) dp[N+1][i] = -inf;
for (int i = N; i >= 1; i--){
int u = tour[i];
for (int j = 1; j <= M; j++)
dp[i][j] = max(dp[tout[u]+1][j-1]+x[u], dp[i+1][j]);
ans = max(ans, dp[i][M]);
}
cout << ans;
return 0;
}
