// Bismi ALlah
#include "bits/stdc++.h"
using namespace std;
signed main () {
int n, d;
cin >> n >> d;
vector <int> g[n], dp(1 << n, 0);
function <int(int,int,int,int)> check=[&](int v, const int mask, int p, int dist) {
if(mask & (1 << v)) {
if(dist >= d) return 1;
return 0;
}
for(auto u : g[v]) {
if(u == p) continue;
if(check(u, mask, v, dist + 1) == 0) return 0;
}
return 1;
};
for(int i = 1; i < n; i ++) {
int p;
cin >> p;
g[i].push_back(p);
g[p].push_back(i);
}
dp[0] = 1;
for(int mask = 0; mask < (1 << n); mask ++) {
for(int i= 0; i < n; i ++) {
if(mask & (1 << i)) {
if(dp[mask ^ (1 << i)]) {
dp[mask] |= check(i, mask ^ (1 << i), -1, 0);
}
}
}
}
int ans = 0;
for(int mask = 0; mask < (1 << n); mask ++) {
if(dp[mask]) ans = max(ans, __builtin_popcount(mask));
}
cout << ans;
return 0;
}
