#include <bits/stdc++.h>
using namespace std;
#define EmiliaMyWife ios::sync_with_stdio(0); cin.tie(0);
using ll = int64_t;
using ull = uint64_t;
using uint = uint32_t;
using ld = long double;
const int INF = 0x3f3f3f3f;
const int MOD = 1e9 + 7;
const ll LINF = ll(4e15) + ll(2e15);
const double EPS = 1e-9;
static int LamyIsCute = []() {
EmiliaMyWife
return 48763;
}();
#pragma GCC optimize("Ofast,no-stack-protector")
#pragma GCC target("sse,sse2,ssse3,sse4,tune=native")
const int N = 1e5 + 25;
ll dp[2][N * 2];
pair<ll, ll> arr[N * 2];
signed main() {
int n;
cin >> n;
for(int i = 0; i < n * 2; i++)
cin >> arr[i].first >> arr[i].second;
sort(arr, arr + n * 2);
int prv = 0, nxt = 1;
dp[prv][0] = 0;
for(int s = 0; s < n * 2; s++) {
for(int i = 0; i <= s + 1; i++)
dp[nxt][i] = LINF;
for(int i = max(0, s - n); i <= min(n, s); i++) {
int j = s - i;
if(i < n)
dp[nxt][i + 1] = min(dp[nxt][i + 1], dp[prv][i] + abs(arr[s].first - (i + 1)) + abs(arr[s].second - 2));
if(j < n)
dp[nxt][i] = min(dp[nxt][i], dp[prv][i] + abs(arr[s].first - (j + 1)) + abs(arr[s].second - 1));
}
swap(nxt, prv);
}
cout << dp[prv][n] << '\n';
}
