//
// main.cpp
// IntensiveCamp 1 2026
//
// Created by Ali AlSalman on 27/04/2026.
//
#include <bits/stdc++.h>
//#define INTERACTIVE
//#define TESTCASES
//#define SPOJ_BULLSCHEI__SZ__E__KIJETESANPAKALU__
#ifndef INTERACTIVE
#define endl '\n'
#endif
template<typename T>
using vec = std::vector<T>;
using namespace std;
struct G {
private:
void dfs(int u, vec<bool> &vis, vec<int> &out, bool vis_flag = true) {
vis[u] = vis_flag;
for (auto v : adj[u]) if (vis[v] != vis_flag)
dfs(v, vis, out, vis_flag);
out.push_back(u);
}
void prepDFS(int u) {
for (auto c : adj[u]) if (c != bin[u][0]) {
depth[c] = depth[u] + 1;
bin[c][0] = u;
prepDFS(c);
}
}
public:
int size;
vec<vec<int>> adj;
vec<array<int, 20>> bin;
vec<int> depth;
G(int n) : size(n), adj(n), bin(n), depth(n) {}
void undirectedAdd(int i, int j) {
adj[i].push_back(j);
adj[j].push_back(i);
}
void prep() {
prepDFS(0);
for (int i = 0; i < size; i++) fill(bin[i].begin() + 1, bin[i].end(), -1);
for (int k = 1; k < 20; k++) for (int i = 0; i < size; i++) if (bin[i][k - 1] != -1)
bin[i][k] = bin[bin[i][k - 1]][k - 1];
}
void raise(int &u, int k) {
if (k == 0) return;
assert(k <= depth[u]);
for (int i = 19; 0 <= i; i--) if ((k>>i)&1)
u = bin[u][i];
}
int lcm(int u, int v) {
if (depth[u] > depth[v]) swap(u, v);
int diff = depth[v] - depth[u];
raise(v, diff);
if (u == v) return u;
for (int i = 19; 0 <= i; i--) {
set s{bin[u][i], bin[v][i]};
if (s.size() == 2 && *s.begin() != -1) {
u = bin[u][i];
v = bin[v][i];
}
}
assert(bin[u][0] == bin[v][0]);
return bin[u][0];
}
int dist(int u, int v) {
int l = lcm(u, v);
return depth[u] + depth[v] - depth[l];
}
};
void solve() {
int n, d;
cin>>n>>d;
G g(n);
for (int i = 1; i < n; i++) {
int u;
cin>>u;
g.undirectedAdd(i, u);
}
g.prep();
int ans = 0;
for (int mask = 1; mask < (1<<g.size); mask++) {
bool validMask = true;
for (int i = 0; i < g.size; i++) if ((mask>>i)&1)
for (int j = i + 1; j < g.size; j++) if ((mask>>j)&1)
validMask &= (g.dist(i, j) >= d);
ans = max(ans, validMask ? __builtin_popcount(mask) : 0);
}
cout<<ans<<endl;
}
int main() {
#ifndef INTERACTIVE
ios::sync_with_stdio(false); cin.tie(nullptr); cout.tie(nullptr);
#endif
int t = 1;
#ifdef TESTCASES
cin>>t;
#endif
for (int i = t; i--;) {
#if defined(TESTCASES) && defined(SPOJ_BULLSCHEI__SZ__E__KIJETESANPAKALU__)
cout<<"Case "<<t-i<<":\n";
#elif defined(SPOJ_BULLSCHEI__SZ__E__KIJETESANPAKALU__)
#warning SPOJ_BULLSCHEIßE__KIJETESANPAKALU__ without TESTCASES doesn't ducking make sense!
#endif
solve();
}
return 0;
}
