#include <bits/stdc++.h>
using namespace std;
// #define int ll
#define MAX LLONG_MAX
#define st first
#define nd second
#define endl '\n'
#define SZ(x) ((int)x.size())
#define ALL(x) x.begin(), x.end()
typedef long long ll;
typedef pair< int, int > ii;
typedef pair< int, ii > iii;
typedef vector< int > vi;
typedef vector< ii > vii;
typedef vector< iii > viii;
typedef vector< vi > vvi;
typedef vector< vii > vvii;
typedef vector< viii > vviii;
const int N = 1e5 + 5;
int m[N][3], a, b;
long long ans;
signed main(){
ios_base::sync_with_stdio(0);
cin.tie(0);
cout.tie(0);
int n; cin >> n;
for(int i=1; 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;
m[x][y]++;
}
for(int i=1; i<=n; i++){
a += m[i][1] - 1, b += m[i][2] - 1;
while(a > 0 and b < 0) a--, b++, ans++;
while(a < 0 and b > 0) a++, b--, ans++;
ans += abs(a) + abs(b);
}
cout << ans;
}
