#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define ull unsigned long long
#define ld long double
#define pii pair<int,int>
#define fi first
#define se second
#define pb push_back
#define clr(f,n) memset(f,0,sizeof(int)*(n))
#define cpy(f,g,n) memcpy(f,g,sizeof(int)*(n))
const int N=200000+5;
struct sdf{
    int to,next;
}eg[2*N];
int head[N],ne=0;
void add(int x,int y){
    eg[++ne]={y,head[x]};
    head[x]=ne;return ;
}
int n;
int sz[N],f[N][2];
void dfs(int pt,int fa){
    sz[pt]=1;
    int mxs=0,mnf1=0,mnf2=0,sum=0;
    for (int i=head[pt];i!=0;i=eg[i].next){
        int v=eg[i].to;
        if (v==fa)continue;
        dfs(v,pt);sz[pt]+=sz[v];
        mxs=max(mxs,sz[v]);
        sum+=f[v][0];
        int now=f[v][1]-f[v][0];
        if (now<mnf1){
            mnf2=mnf1;mnf1=now;
        }else mnf2=min(mnf2,now);
    }
    f[pt][0]=2*sz[pt]+sum+min(-2*mxs,mnf1+mnf2);
    f[pt][1]=sum+mnf1;
    return ;
}
int main(){
	freopen ("shujihuo.in","r",stdin);
	freopen ("shujihuo.out","w",stdout);
	scanf("%d",&n);
	for (int i=2;i<=n;i++){
	    int p;scanf("%d",&p);add(i,p);add(p,i);
    }
    dfs(1,0);
    printf("%d\n",f[1][0]);
}