#include <bits/stdc++.h>
using namespace std;
typedef pair<int,int> pii;
typedef vector<int> vi;
typedef long long ll;
typedef pair<ll,ll> pll;
typedef tuple<int,int,int> ti;
typedef unsigned long long ull;
typedef long double ld;
typedef vector<ll> vll;
typedef pair<ld,ld> pld;
#define pb push_back
#define popb pop_back()
#define pf push_front
#define popf pop_front
#define ff first
#define ss second
#define MOD (ll)(1000000007)
#define INF (ll) (1e18)
#define all(v) (v).begin(),(v).end()
const int nx[8] = {0, 0, 1, -1,1,1,-1,-1}, ny[8] = {1, -1, 0, 0,1,-1,1,-1}; //East, West, South, North+
ll gcd(ll a , ll b) {return b ? gcd(b , a % b) : a ;}
ll lcm(ll a, ll b){return (a / gcd(a, b)) * b;}
////////////******SOLUTION******\\\\\\\\\\\
const int MAX_N = 1504;
int n, d;
int dist[MAX_N][MAX_N];
set<int> seen;
vi adj[MAX_N];
int par[MAX_N];
void f(int x, int par)
{
dist[x][par] = dist[par][x] = 1;
seen.insert(x);
for(int y = 0; y <n; y ++)
{
if(y == x)
dist[x][y] = 0;
if(y == par) continue;
if(seen.count(y) != 0)
dist[x][y] = dist[y][x] = dist[par][y] + 1;
}
//cout << x << ' ' << par << '\n' << flush;
if(adj[x].size() == 0)
return;
for(auto e: adj[x])
f(e,x);
//cout << x << " returning\n" << flush;
return ;
}
void solve()
{
cin >> n >> d;
memset(dist,-1,sizeof(dist));
for(int i = 1; i <n; i++)
{
cin >> par[i];
adj[par[i]].pb(i);
}
f(0,n);
int ans = 1;
for(int mask = 1; mask < (1 << n); mask ++)
{
//cout << mask << '\n' << flush;
vi nodes;
for(int i = 0; i < n; i ++)
if(mask & (1<<i))
nodes.pb(i);
bool flag = true;
for(int i = 0; i < nodes.size()-1; i ++)
{
for(int j = i + 1; j < nodes.size(); j ++)
{
//cout << i << ' ' << j << ' ' << mask << '\n' << flush;
if(dist[nodes[i]][nodes[j]] < d)
{
flag = false;
break;
}
}
}
if(flag)
ans = max(ans,(int)(nodes.size()));
//cout << '\t' << ans << '\n' << flush;
}
cout << ans;
return ;
}
int main()
{
ios::sync_with_stdio(false);
cin.tie(0); cout.tie(0);
int tt =1;
while(tt--)
{
solve();
}
}
/*
*/
