#include <bits/stdc++.h>
    
using namespace std;
    
typedef long long ll;
const int  N = 1e2 + 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]);
}
void test() {
    cin >> n;
    for(int i = 2; i <= n; i++) {
        int p;
        cin >> p;
        g[p].push_back(i);
    }
    dfs(1);
    vector<int> p(n);
    iota(p.begin(), p.end(), 1);
    ll mx = 0;
    do
    {
        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]];
            }
        }
        mx = max(mx, x);
    } while (next_permutation(p.begin(), p.end()));
    cout << res - mx << '\n';
}
int main() {
    ios_base::sync_with_stdio(false);
    cin.tie(0); 
    
    int t = 1; 
    // cin >> t;
    
    while(t--) 
        test();
    return 0;
}