1 #include<iostream>
2 #include<cstdio>
3 #include<algorithm>
4 #include<cstring>
5 using namespace std;
6 const int maxn=1007;
7 const int INF=0x7f7f7f7f;
8 int n,ans;
9 int fa[maxn],a[maxn],dis[maxn],dep[maxn];
10 bool cmp(int x,int y){
11 return dep[x]>dep[y];
12 }
13 int main(){
14 memset(dis,INF,sizeof(dis));
15 cin>>n;a[1]=1;fa[1]=0;
16 for(int i=2;i<=n;i++){
17 cin>>fa[i];a[i]=i;
18 dep[i]=dep[fa[i]]+1;
19 }
20 sort(a+1,a+n+1,cmp);
21 for(int i=1;i<=n;i++){
22 int u=a[i];int v=fa[u];int w=fa[v];
23 dis[u]=min(dis[u],min(dis[v]+1,dis[w]+2));
24 if(dis[u]>2){
25 dis[w]=0;ans++;
26 dis[fa[w]]=min(dis[fa[w]],1);
27 dis[fa[fa[w]]]=min(dis[fa[fa[w]]],2);
28 }
29 }
30 cout<<ans<<endl;
31 return 0;
32 }
