#include<bits/stdc++.h>
#define ci const int
using namespace std;
#define ll long long
#define rep(i, x, y) for(int i = (x), stOxrj = (y); i <= stOxrj; ++i)
#define irep(i, x, y) for(int i = (x), stOxrj = (y); i >= stOxrj; --i)
#define pb emplace_back
#define all(S) S.begin(), S.end()
#define Size(S) (int)S.size()
#define fi first
#define se second
#define il inline
#define let const auto
using pii = pair<int, int>;
using vint = vector<int>;
template<typename T>
il void tmax(T &x, const T &y) { if(x < y) x = y; }
template<typename T>
il void tmin(T &x, const T &y) { if(x > y) x = y; }
il int read() {
    int res = 0, flag = 1; char c = getchar();
    while(c < '0' || c > '9') { if(c == '-') flag = -1; c = getchar(); }
    while(c >= '0' && c <= '9') res = res * 10 + c - '0', c = getchar();
    return res * flag;
}
const int N = 5e5 + 20;
vint G[N];
vint ans[N];
int pr[N], ct;
int newn(vint sons, vint s) {
    ans[++ct] = s;
    for(int x : sons) pr[x] = ct;
    return ct;
}
tuple<int, int, int> dfs(int u, int faz) {
    if(!G[u].size()) return make_tuple(newn({}, {u, faz}), u, u);
    int al, lstr, id = 0;
    for(int v : G[u]) {
        auto [nid, l, r] = dfs(v, u);
        if(!id) {
            al = l, lstr = r;
            id = newn({nid}, {u, l, r});
            continue;
        } 
        id = newn({id}, {u, al, lstr, l});
        id = newn({id, nid}, {u, al, l, r});
        lstr = r;
    }
    if(!faz) return make_tuple(0, 0, 0);
    return make_tuple(newn({id}, {u, faz, al, lstr}), al, lstr);
}
signed main() { 
    // freopen("1.in", "r", stdin); 
    int n = read();
    rep(i, 2, n) G[read()].pb(i);
    dfs(1, 0);
    cout << ct << '\n';
    rep(i, 1, ct) {
        set<int> s;
        for(int x : ans[i]) s.insert(x);
        cout << s.size() << '\n';
        for(int x : s) cout << x << ' ';
        cout << '\n';
    }
    rep(i, 1, ct - 1) cout << i << ' ' << pr[i] << '\n';
    return 0;
}