#include <bits/stdc++.h>
using namespace std;
using ll = long long;

int n;
vector<int> v[100100];

int ans;

int dfs(int u) {
    if(v[u].empty()) return 1;

    int re = 0;
    for(auto x : v[u]) re += dfs(x);
    if(re > 1) ans++, re = 0;
    return re;
}

int main() {
    cin.tie(0)->sync_with_stdio(0);
    cin >> n;
    for(int i=2;i<=n;i++) {
        int p; cin >> p;
        v[p].push_back(i);
    }
    dfs(1);
    cout << ans;
}