#include <bits/stdc++.h>
#define f first
#define s second
using namespace std;
const int N = 310;
const int K = 5;
int n, d;
int up[N][K], tin[N], tout[N], timer, dep[N];
vector<int> g[N];
bool anc(int a, int b) {
return tin[a] <= tin[b] && tout[a] >= tout[b];
}
int lca(int a, int b) {
if (anc(a, b))
return a;
else if (anc(b, a))
return b;
for (int i = K - 1;i >= 0;i--) {
if (!anc(up[a][i], b) && up[a][i] > 0)
a = up[a][i];
}
return up[a][0];
}
void dfs(int v, int p) {
tin[v] = ++timer;
up[v][0] = p;
dep[v] = dep[p] + 1;
for (int i = 1;i < K;i++)
up[v][i] = up[up[v][i - 1]][i - 1];
for (auto u : g[v]) {
if (u == p)
continue;
dfs(u, v);
}
tout[v] = timer;
}
int main() {
ios::sync_with_stdio(false);
cin.tie(0);
cout.tie(0);
int tt = 1;
//cin >> tt;
while (tt--) {
cin >> n >> d;
for (int i = 2;i <= n;i++) {
int x;
cin >> x;
++x;
g[x].push_back(i);
g[i].push_back(x);
}
dfs(1, 0);
int ans = 0;
for (int mask = 1;mask < (1 << n);mask++) {
int ok = 1;
for (int i = 0;i < n;i++) {
if (mask >> i & 1) {
for (int j = 0;j < n;j++) {
if (i == j)
continue;
if (mask >> j & 1) {
int dis = dep[i + 1] + dep[j + 1] - 2 * dep[lca(i + 1, j + 1)];
ok &= (dis >= d);
}
}
}
}
if (ok) {
ans = max(ans, __builtin_popcount(mask));
}
}
cout << ans;
}
return 0;
}
