#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], P[N], pp[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;
}
bool ii = 1;
int l[N], r[N];
bool cmp(int x, int y) {
    return s[x] > s[y];
}
int get(int v) {
    if(pp[v] == v) return v;
    return pp[v] = get(pp[v]);
}
void merge(int a, int b) {
    a = get(a);
    b = get(b);
    pp[a] = b;
}
void test() {
    cin >> n;
    for(int i = 2; i <= n; i++) {
        int p;
        cin >> p;
        P[i] = p;
        g[p].push_back(i);
    }
    for(int i = 1; i <= n; i++) {
        pp[i] = i;
    }
    dfs(1);
    memset(l, -1, sizeof(l));
    memset(r, -1, sizeof(r));
    vector<int> p(n);
    iota(p.begin(), p.end(), 1);
    sort(p.begin(), p.end(), cmp);
    for(int i:p) {
        int v = P[i];
        while(v) {
            if(get(v) == get(i)) {
                v = P[v];
                continue;
            }
            if(l[v] == -1 && r[i] == -1) {
                l[v] = i;
                r[i] = v;
                merge(v, i);
                break;
            }
            else if(r[v] == -1 && l[i] == -1) {
                r[v] = i;
                l[i] = v;
                merge(v, i);
                break;
            }
            v = P[v];
            break;
        }
        v = P[i];
        while(v) {
            if(get(v) == get(i)) {
                v = P[v];
                continue;
            }
            if(l[v] == -1 && l[i] != v && r[i] != v && r[i] == -1) {
                l[v] = i;
                r[i] = v;
                merge(v, i);
                break;
            }
            else if(r[v] == -1 && l[i] != v && r[i] != v && l[i] == -1) {
                r[v] = i;
                l[i] = v;
                merge(v, i);
                break;
            }
            v = P[v];
            break;
        }
        if(l[i] == -1 && r[i] == -1 && i != 1) {
            if(l[1] == -1) {
                l[1] = i;
                r[i] = 1;
                merge(i, 1);
            } else if(r[1] == -1) {
                r[1] = i;
                l[i] = 1;
                merge(i, 1);
            }
        }
    }
    ll x = 0;
    for(int i = 1; i <= n; i++) {
        if(r[i] != -1) {
            if(is(r[i], i)) {
                x += 2 * s[i];
            } else if(is(i, r[i])) {
                x += 2 * s[r[i]];
            }
        }
    }
    cout << res - x << '\n';
}
int main() {
    ios_base::sync_with_stdio(false);
    cin.tie(0); 
    
    int t = 1; 
    // cin >> t;
    
    while(t--) 
        test();
    return 0;
}