#include<iostream>
#include<string>
#include<stack>
#include<queue>
#include<string.h>
#include<map>
#include<unordered_map>
#include<vector>
#include<cmath>
#include<iostream>
#include<algorithm>
using namespace std;
typedef long long ll;
const int maxn = 205;
const int maxm = 500;
#define lson rt<<1,l,mid
#define rson rt<<1|1,mid+1,r
inline int read()
{
    int f = 1, num = 0;
    char ch = getchar();
    while (0 == isdigit(ch)) { if (ch == ‘-‘)f = -1; ch = getchar(); }
    while (0 != isdigit(ch)) num = (num << 1) + (num << 3) + ch - ‘0‘, ch = getchar();
    return num * f;
}
struct edge {
    int to, nxt;
}e[maxm];
int hd[maxn], tot;
void add(int f, int t) {
    e[++tot].to = t;
    e[tot].nxt = hd[f];
    hd[f] = tot;
}
int n, m;
bool st[maxn];
int dp[maxn][maxn],sp[maxn];
int val[maxn];
void dfs(int u, int last) {
    if (last == 0)return;
    for (int i = 1; i <= last; i++)dp[u][i] = val[u];
    for (int i = hd[u]; i; i = e[i].nxt) {
        int v = e[i].to;
        dfs(v, last - 1);
        for (int i = last; i >= 1; i--) {
            for (int j = 1; j<= i-1; j++) {
                dp[u][i] = max(dp[u][i], dp[u][i - j] + dp[v][j]);
            }
        }
    }
}
int main() {
    //freopen("test.txt", "r", stdin);
    while (scanf("%d%d", &n, &m) && n) {
        memset(hd, 0, sizeof(hd));
        memset(st, 0, sizeof(st));
        memset(sp, 0, sizeof(sp));
        memset(dp, 0, sizeof(dp));
        tot = 0;
        for (int i = 1; i <= n; i++) {
            int a = read(), b = read();
            val[i] = b;
            if (a == 0) st[i] = 1;
            else { add(a, i); }
        }
        for (int i = 1; i <= n; i++) {
            if (st[i]) {//对没棵树进行树上背包
                dfs(i,m);
            }
        }
        for (int i = 1; i <= n; i++) {//最后对每颗树做松弛操作
            if (st[i]) {
                for (int s = m; s >= 1; s--) {
                    for (int j = 1; j<= s; j++) {
                        sp[s] = max(sp[s], sp[s - j] + dp[i][j]);
                    }
                }
            }
        }
        cout << sp[m] << endl;
    }
    return 0;
}