#include <bits/stdc++.h>
    
using namespace std;
    
typedef long long ll;
const int  N = 1e6 + 12, MOD = (int)1e9 + 7;


int n, tin[N], tout[N], timer = 0, s[N];

ll res = 0;
vector<int> g[N];
void dfs(int v) {
    tin[v] = ++timer;
    s[v] = 1;
    for(int to:g[v]) {
        dfs(to);
        s[v] += s[to];
    }
    res += s[v] * 2ll;
    tout[v] = ++timer;
}
bool is(int v, int u) {
    return (tin[v] <= tin[u] && tout[u] <= tout[v]);
}
ll calc(deque<int> &p) {
    ll x = 0;
    for(int i = 1; i < n; i++) {
        if(is(p[i], p[i - 1])) {
            x += 2 * s[p[i - 1]];
        } else if(is(p[i - 1], p[i])) {
            x += 2 * s[p[i]];
        }
    }
    return x;
}

ll dp[N][2];

void go(int v) {
    ll sum = 0;
    vector<ll> d;
    for(int to:g[v]) {
        go(to);
        sum += dp[to][1];
        d.push_back(dp[to][0] - dp[to][1] + s[to] * 2);
    }
    sort(d.rbegin(), d.rend());
    dp[v][1] = dp[v][0] = sum;
    for(int i = 0; i < min((int)d.size(), 2) && d[i] >= 0; i++) {
        if(i <= 0) {
            dp[v][0] += d[i];
        }
        dp[v][1] += d[i];
    }
}
void test() {
    cin >> n;
    for(int i = 2; i <= n; i++) {
        int p;
        cin >> p;
        g[p].push_back(i);
    }
    dfs(1);
    go(1);
    cout << res - max(dp[1][1], dp[1][0]) << '\n';
}
int main() {
    ios_base::sync_with_stdio(false);
    cin.tie(0); 
    
    int t = 1; 
    // cin >> t;
    
    while(t--) 
        test();
    return 0;
}