#include <bits/stdc++.h>
using namespace std;
const int MAX_N = 1000;
const long long INF = 1e18;
vector<int> a, b;
long long dp[2 * MAX_N + 1][MAX_N + 1];
int main() {
int n;
long long ans = 0;
cin >> n;
for ( int i = 0; i < 2 * n; i++ ) {
int x, y;
cin >> x >> y;
if ( x < 1 ) {
ans += 1 - x;
x = 1;
} else if ( x > n ) {
ans += x - n;
x = n;
}
if ( y < 1 ) {
ans += 1 - y;
y = 1;
} else if ( y > 2 ) {
ans += y - 2;
y = 2;
}
if ( y == 1 )
a.push_back( x );
else
b.push_back( x );
}
if ( a.size() > b.size() )
swap( a, b );
sort( a.begin(), a.end() );
sort( b.begin(), b.end() );
for ( int c = 0; c <= n; c++ ) {
for ( int i = 0; i <= n; i++ )
dp[c][i] = INF;
}
dp[0][0] = 0;
for ( int c = 1; c <= n; c++ ) {
for ( int i = 0; i <= c; i++ ) {
int j = 2 * c - i;
if ( i <= a.size() && j <= b.size() ) {
if ( i >= 2 )
dp[c][i] = min( dp[c][i], dp[c - 1][i - 2] + abs( a[i - 2] - c ) + abs( a[i - 1] - c ) + 1 );
if ( i >= 1 && j >= 1 )
dp[c][i] = min( dp[c][i], dp[c - 1][i - 1] + abs( a[i - 1] - c ) + abs( b[j - 1] - c ) );
if ( j >= 2 )
dp[c][i] = min( dp[c][i], dp[c - 1][i] + abs( b[j - 2] - c ) + abs( b[j - 1] - c ) + 1 );
}
}
}
cout << ans + dp[n][a.size()] << "\n";
}
