#include <bits/stdc++.h>
using namespace std;
const int N = 100000 + 5;
const int INF = 1 << 20;

int d[N];
vector<int> G[N];

int dp[N][2];

void dfs(int u, int f) {
    int cr = 0;
    for (int v: G[u]) {
        if (v == f) continue;
        dfs(v, u);
        ++cr;
    }
    if (cr == 0) {
        dp[u][0] = 1;
        dp[u][1] = 0;
    } else {
        int cvr = 1, ncvr = 0, mi = INF;
        for (int v: G[u]) {
            if (v == f) continue;
            cvr += min(dp[v][0], dp[v][1]);
            ncvr += dp[v][0];
            dp[u][1] += dp[v][0];
            mi = min(mi, dp[v][1] - dp[v][0]);
        }
        dp[u][0] = min(cvr, ncvr);
        dp[u][1] += mi;
    }
}

int main() {
    cin.tie(nullptr)->sync_with_stdio(false);
    int n; cin >> n;
    if (n <= 2) {
        cout << 1 << '\n';
        return 0;
    }
    for (int i = 2; i <= n; ++i) {
        int u; cin >> u;
        G[u].push_back(i);
        G[i].push_back(u);
        d[i]++;
        d[u]++;
    }

    int r = 1;
    for (int i = 1; i <= n; ++i) {
        if (d[i] != 1) r = i;
    }

    dfs(r, r);

    cout << min(dp[r][0], dp[r][1]) << '\n';
    return 0;
}