#include "bits/stdc++.h"
#define rep(i,a,n) for(auto i=a;i<=n;i++)
#define per(i,a,n) for(auto i=n;i>=a;i--)
#define pb push_back
#define mp make_pair
#define FI first
#define SE second
#define all(A) A.begin(),A.end()
#define sz(A) (int)A.size()
template<class T> inline bool chmax(T &a, T b) { if(a < b) {a = b; return 1;} return 0; }
template<class T> inline bool chmin(T &a, T b) { if(b < a) {a = b; return 1;} return 0; }
using namespace std;

template<class A, class B> string to_string(pair<A, B> p);
string to_string(const string &s) { return '"' + s + '"'; }
string to_string(const char *s) { return to_string((string) s); }
string to_string(char c) { return "'" + string(1, c) + "'"; }
string to_string(bool x) { return x ? "true" : "false"; }
template<class A> string to_string(A v) 
{
    bool first = 1;
    string res = "{";
    for(const auto &x: v) 
    {
        if (!first) res += ", ";
        first = 0;
        res += to_string(x);
    }
    res += "}";
    return res;
}
template<class A, class B> string to_string(pair<A, B> p) { return "(" + to_string(p.FI) + ", " + to_string(p.SE) + ")"; }

void debug_out() { cerr << endl; }
template<class Head, class... Tail> void debug_out(Head H, Tail... T) 
{
    cerr << " " << to_string(H);
    debug_out(T...);
}
#ifndef ONLINE_JUDGE
    #define debug(...) cerr << "[" << #__VA_ARGS__ << "]:", debug_out(__VA_ARGS__)
#else
    #define debug(...) if(0) puts("No effect.")
#endif

using ll = long long;
// using LL = __int128;
using pii = pair<int,int>;
using vi = vector<int>;
using db = double;
using ldb = long double;

const int maxn = 100'000;
const int inf = 0x3f3f3f3f;
const int mod = 1e9 + 7;

int main()
{
    int n; scanf("%d", &n);
    static vi e[maxn + 5];
    rep(i, 2, n)
    {
        int f; scanf("%d", &f);
        e[f].pb(i);
        e[i].pb(f);
    }
    if(n <= 2) return puts("1"), 0;
    static int dp[maxn + 5][3];
    function<void(int, int)> dfs = [&](int now, int fa)
    {
        int best = 0;
        for(auto v: e[now]) if(v != fa)
        {
            dfs(v, now);
            dp[now][0] += min({dp[v][0], dp[v][1], dp[v][2]});
            dp[now][1] += dp[v][0];
            dp[now][2] += dp[v][0];
            chmin(best, dp[v][1] - dp[v][0]);
        }
        dp[now][0]++;
        dp[now][2] += best;
        // debug(now, dp[now][0], dp[now][1], dp[now][2]);
    };
    int rt = 1;
    rep(i, 1, n) if(sz(e[i]) > 1) { rt = i; break; }
    dfs(rt, 0);
    int ans = min({dp[rt][0], dp[rt][1], dp[rt][2]});
    printf("%d\n", ans);
    return 0;
}