#include <bits/stdc++.h>
using namespace std;
#define int long long
int n;
int a[5][100005];
int solve(int c)
{
if (c == n + 1)
return 0;
int x = a[1][c],y = a[2][c];
x--;
y--;
//cout << c << ' ' << x << ' ' << y << endl;
if (x >= 0 and y >= 0)
{
a[1][c + 1] += x;
a[2][c + 1] += y;
//cout << c << ' ' << x + y << endl;
return x + y + solve(c + 1);
}
if (x < 0 and y >= 0)
{
int md = min(y,-x);
int cresc = md;
x += md;
y -= md;
cresc += -x + y;
a[1][c + 1] += x;
a[2][c + 1] += y;
//cout << c << ' ' << cresc << endl;
return cresc + solve(c + 1);
}
else if (x >= 0 and y < 0)
{
int md = min(x,-y);
int cresc = md;
y += md;
x -= md;
cresc += -y + x;
a[1][c + 1] += x;
a[2][c + 1] += y;
//cout << c << ' ' << cresc << endl;
return cresc + solve(c + 1);
}
else
{
a[1][c + 1] += x;
a[2][c + 1] += y;
//cout << c << ' ' << -x - y << endl;
return -x - y + solve(c + 1);
}
}
signed main()
{
ios_base::sync_with_stdio(false);
cin.tie(NULL);
cout.tie(NULL);
cin >> n;
int ans = 0;
for (int i = 1; i <= 2 * n; i++)
{
int x,y;
cin >> x >> y;
if (x < 1)
{
ans += 1 - x;
x = 1;
}
if (x > n)
{
ans += x - n;
x = n;
}
if (y < 1)
{
ans += 1 - y;
y = 1;
}
if (y > 2)
{
ans += y - 2;
y = 2;
}
a[y][x]++;
}
ans += solve(1);
cout << ans;
return 0;
}
