/* Author: Nguyen Chi Thanh - High School for the Gifted - VNU.HCM (i2528) */ #include <bits/stdc++.h> using namespace std; #define int long long #define ull unsigned long long #define ld long double #define pii pair<int, int> #define fi first #define se second #define __builtin_popcount __builtin_popcountll #define all(x) (x).begin(), (x).end() #define BIT(x, i) (((x) >> (i)) & 1) #define MASK(x) ((1ll << (x))) #define debug(a, l, r) for (int _i = (l); _i <= (r); ++_i) cout << (a)[_i] << ' '; cout << '\n'; const int MAXN = 1e5 + 5; const int INF = 1e18 + 5; int n; pii coins[MAXN]; void init() { cin >> n; for (int i = 1; i <= 2 * n; ++i) cin >> coins[i].fi >> coins[i].se; } namespace subtask1 { bool check() {return n <= 10;} void solve() { vector<pii> des(2 * n + 5); for (int i = 1; i <= n; ++i) des[i] = {i, 1}; for (int i = 1; i <= n; ++i) des[i + n] = {i, 2}; n = 2 * n; // For easier implementation vector<vector<int>> dp(MASK(n) + 5, vector<int>(n + 5, INF)); auto dist = [&] (pii &x, pii &y) { return abs(x.fi - y.fi) + abs(x.se - y.se); }; for (int mask = 0; mask < MASK(n); ++mask) { for (int i = 0; i < n; ++i) { if (!BIT(mask, i)) continue; if (__builtin_popcount(mask) == 1) { dp[mask][i] = dist(coins[i + 1], des[i + 1]); continue; } int lst = __builtin_popcount(mask); int pmask = mask ^ MASK(i); int best = INF; for (int j = 0; j < n; ++j) { if (!BIT(pmask, j)) continue; best = min(best, dp[pmask][j]); } if (best < INF) dp[mask][i] = best + dist(coins[i + 1], des[lst]); } } int res = INF; for (int i = 0; i < n; ++i) res = min(res, dp[MASK(n) - 1][i]); cout << res; } } signed main() { #ifdef NCTHANH freopen("input.txt", "r", stdin); freopen("output.txt", "w", stdout); #endif ios_base::sync_with_stdio(0); cin.tie(nullptr); cout.tie(nullptr); init(); if (subtask1::check()) return subtask1::solve(), 0; return 0; }