// #pragma GCC optimize("O3,Ofast,unroll-loops")
#include <bits/stdc++.h>
using namespace std;
#define now chrono::steady_clock::now().time_since_epoch().count()
#define speedup cin.tie(0)->sync_with_stdio(0)
#define bitcount __builtin_popcount
#define all(x) begin(x), end(x)
#define pb push_back
#define vc vector
using ld = double;
using pii = array<int, 2>;
const int inf = 1e9;
inline bool chmin(int &a, int b) {if (a > b) {a = b; return 1;} return 0;}
inline bool chmax(int &a, int b) {if (a < b) {a = b; return 1;} return 0;}
inline void solve() {
int n, D;
cin >> n >> D;
vc<vc<int>> adj(n);
for (int b = 1; b < n; b++) {
int a; cin >> a;
adj[a].pb(b);
adj[b].pb(a);
}
auto good = [&](int mask) -> bool {
int st = __lg(mask);
// bitset<20> t(mask);
// cout << t << '\n';
vc<int> d (n, -1);
queue<int> q;
q.push(st);
d[st] = 0;
while (q.size()) {
int a = q.front(); q.pop();
for (int b : adj[a]) {
if (d[b] != -1) continue;
if (mask >> b & 1) {
if (d[a] + 1 < D) return 0;
d[b] = 0;
} else d[b] = d[a] + 1;
q.push(b);
}
}
// for (int i : d) cout << i << ' ';
// cout << "\n\n";
return 1;
};
int ans = 0;
for (int mask = 1; mask < (1 << n); mask++)
if (good(mask)) chmax(ans, bitcount(mask));
cout << ans;
}
signed main() {
speedup;
solve();
return 0;
}
