#ifndef hwe
#include "migrations.h"
#endif
#include <bits/stdc++.h>
using namespace std;
#define POPCOUNT(n) (__builtin_popcountll((n)))
#define CLZ(n) (__builtin_clzll((n)))
#define CTZ(n) (__builtin_ctzll((n)))
#define LOG(n) (63 - __builtin_clzll((n)))
#define BIT(n, i) (((n) >> (i)) & 1ll)
#define MASK(i) (1ll << (i))
#define FLIP(n, i) ((n) ^ (1ll << (i)))
#define ON(n, i) ((n) | MASK(i))
#define OFF(n, i) ((n) & ~MASK(i))
#define Int __int128
#define fi first
#define se second
typedef long long ll;
typedef unsigned long long ull;
typedef long double ld;
typedef pair<int, int> pii;
typedef pair<long long, long long> pll;
typedef pair<long long, int> pli;
typedef pair<int, long long> pil;
typedef vector<pair<int, int>> vii;
typedef vector<pair<long long, long long>> vll;
typedef vector<pair<long long, int>> vli;
typedef vector<pair<int, long long>> vil;
template <class T1, class T2> bool maximize(T1 &x, T2 y) {
if (x < y) {
x = y;
return true;
}
return false;
}
template <class T1, class T2> bool minimize(T1 &x, T2 y) {
if (x > y) {
x = y;
return true;
}
return false;
}
template <class T> void remove_duplicate(vector<T> &ve) {
sort (ve.begin(), ve.end());
ve.resize(unique(ve.begin(), ve.end()) - ve.begin());
}
mt19937_64 rng(chrono::high_resolution_clock::now().time_since_epoch().count());
long long random(long long l, long long r) {
return uniform_int_distribution<long long>(l, r)(rng);
}
template <class T> T random(T r) {
return rng() % r;
}
const int N = 10000;
const int MOD = 1e9 + 7;
const int inf = 1e9;
const long long INF = 1e18;
int dist[N], maxDist = -1, ans = -1, ans1 = -1;
int send_message(int n, int u, int pu) {
const int bits[] = {n - 12, n - 11, n - 10, n - 8, n - 7, n - 6, n - 4};
if (u == bits[0]) ans1 = ans; // max pre
dist[u] = dist[pu] + 1;
if (maximize(maxDist, dist[u])) ans = u;
if (u < bits[0]) return 0;
int pos = -1;
for (int i = 0; i < 7; ++i)
if (bits[i] == u) pos = i;
if (pos != -1) {
return (BIT(ans1, 2 * pos + 1) << 1) | BIT(ans1, 2 * pos);
}
if (u % 4 == 3) {
for (int i = 1; i <= 4; ++i)
if (ans == u - 4 + i) return i;
return 0;
}
return 0;
}
pii longest_path(vector<int> S) {
int n = S.size();
const int bits[] = {n - 12, n - 11, n - 10, n - 8, n - 7, n - 6, n - 4};
int ans1 = 0;
for (int i = 0; i < 7; ++i) {
int x = BIT(S[bits[i]], 0);
int y = BIT(S[bits[i]], 1);
if (x) ans1 |= MASK(2 * i);
if (y) ans1 |= MASK(2 * i + 1);
cerr << S[bits[i]] << '\n';
}
int ans = 0;
for (int i = n - 9; i < n; i += 4) if (S[i] != 0) {
ans = i - 4 + S[i];
}
if (ans == 0) return make_pair(0, ans1);
return make_pair(0, ans);
}
#ifdef hwe
signed main() {
// int n; cin >> n;
int n = 10000;
vector<int> p(n);
for (int i = 1; i < n; ++i) p[i] = i - 1;
// for (int i = 1; i < n; ++i) cin >> p[i];
vector<int> S(n);
for (int i = 1; i < n; ++i) S[i] = send_message(n, i, p[i]);
pii ans = longest_path(S);
cerr << ans.fi << ' ' << ans.se << '\n';
return 0;
}
#endif
