#include <bits/stdc++.h>
using namespace std;
template <class X, class Y>
bool cmax(X &a, const Y &b) {
return a < b ? a = b, 1 : 0;
}
const int N = 2e5 + 5;
const int D = 500;
int dp[N][D], n, d, siz[N];
vector<int> adj[N];
void dfs1(int u) {
dp[u][0] = 1;
for (int v : adj[u]) {
dfs1(v);
for (int i = 0; i <= d; i++)
cmax(dp[u][i], max(dp[v][max(i, d - i)] +
dp[u][i], dp[v][i] + dp[u][max(i, d - i)]));
}
for (int i = d; i >= 0; i--)
dp[u][i + 1] = dp[u][i];
for (int i = d; i >= 0; i--)
cmax(dp[u][i], dp[u][i + 1]);
}
void dfs2(int u) {
dp[u][0] = d - 1; dp[u][1] = 0;
for (int v : adj[u]) {
dfs2(v); siz[u] += siz[v] + 1;
for (int i = siz[u] / d + 1; i >= 0; i--)
for (int j = min(i, siz[v] / d + 1); j >= 0; j--)
if (dp[u][i - j] + dp[v][j] + 1 >= d)
cmax(dp[u][i], min(dp[u][i - j], dp[v][j] + 1));
}
}
int main() {
cin.tie(0)->sync_with_stdio(0);
cin >> n >> d;
for (int i = 1; i < n; i++) {
int p; cin >> p; adj[p].push_back(i);
}
if (d + 1 < D) {
dfs1(0); cout << dp[0][0];
} else {
memset(dp, 0xc0, sizeof dp); dfs2(0);
for (int i = D - 1; i >= 0; i--)
if (dp[0][i] >= 0) {
cout << i; break;
}
}
}
