#include<iostream> #include<vector> #include<algorithm> using namespace std; const int MAX_N=2e5+5; int n,D; vector<int>g[MAX_N]; vector<int>dp[MAX_N]; int height[MAX_N]; int ans=1; void merge(int u,int v) { if(u==0) { if(dp[u].size()>D-1)ans=max(ans,dp[u][dp[u].size()-1-(D-1)]); } for(int curdepth=0;curdepth<dp[v].size();curdepth++) { int curval=dp[v][dp[v].size()-1-curdepth]; int otherdepth=max(curdepth+1,D-curdepth-1); if(u==0) { int ansdepth=D-curdepth-1; if(ansdepth>=dp[u].size())continue; int curbest=curval+dp[u][dp[u].size()-1-ansdepth]; ans=max(ans,curbest); } if(otherdepth>=dp[u].size())continue; curval+=dp[u][dp[u].size()-1-otherdepth]; dp[v][dp[v].size()-1-curdepth]=curval; } for(int newdepth=dp[v].size();newdepth>=1;newdepth--) { int curval=dp[v][dp[v].size()-1-(newdepth-1)]; int pos=dp[u].size()-1-newdepth; dp[u][pos]=max(dp[u][pos],curval); if(pos)dp[u][pos]=max(dp[u][pos],dp[u][pos-1]); } vector<int>().swap(dp[v]); if(u==0) { if(dp[u].size()>D)ans=max(ans,1+dp[u][dp[u].size()-1-D]); } } void initdfs(int u,int par) { height[u]=1; for(int v:g[u]) { if(v==par)continue; initdfs(v,u); height[u]=max(height[u],height[v]+1); } } void dfs(int u,int par) { int mx=-1,bigchild=-1; for(int v:g[u]) { if(v==par)continue; if(height[v]>mx) { mx=height[v]; bigchild=v; } } if(bigchild==-1) { dp[u].push_back(1); return; } dfs(bigchild,u); swap(dp[bigchild],dp[u]); vector<int>().swap(dp[bigchild]); int d1=0; if(dp[u].size()>D-1)d1=dp[u][dp[u].size()-1-(D-1)]; dp[u].push_back(max(dp[u].back(),d1+1)); for(int v:g[u]) { if(v==par or v==bigchild)continue; dfs(v,u); merge(u,v); } } int main () { ios_base::sync_with_stdio(false); cin.tie(NULL); cout.tie(NULL); cin>>n>>D; for(int i=1;i<n;i++) { int x; cin>>x; g[x].push_back(i); g[i].push_back(x); } initdfs(0,-1); dfs(0,-1); cout<<ans<<"\n"; return 0; }