#include<bits/stdc++.h>
using namespace std;
const int N = (int)2e5+7;
const int inf = (int)1e9+7;
int n, dp[N][2];
vector<int> g[N];
int l[N], r[N];
int a[N], tin[N], tout[N], timer;
void dfs(int v, int pr) {
tin[v] = ++timer;
l[v] = tin[v];
for(auto to : g[v]) {
if(to == pr) {
continue;
}
dfs(to, v);
}
tout[v] = timer;
r[v] = tout[v];
}
int main() {
ios_base::sync_with_stdio(false);
cin.tie(0);
int m;
cin >> n >> m;
int root = 0;
for(int i = 1; i <= n; i++) {
int pr;
cin >> pr;
cin >> a[i];
if(pr == 0) {
root = i;
} else {
g[pr].push_back(i);
}
}
dfs(root, 0);
for(int k = 1; k <= m; k++) {
//1 = k
//0 = k-1
for(int i = 1; i <= n; i++) {
dp[r[i]][1] = max(dp[r[i]][1], dp[l[i]-1][0]+a[i]);
}
for(int i = 1; i <= n; i++) {
dp[i][1] = max(dp[i][1], dp[i-1][1]);
}
for(int i = 0; i <= n; i++) {
dp[i][0] = dp[i][1];
dp[i][1] = -inf;
}
}
cout << dp[n][0];
return 0;
}
