#include <bits/stdc++.h>
#pragma GCC optimize ("O2,unroll-loops")
//#pragma GCC optimize("no-stack-protector,fast-math")
//#pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,tune=native")
using namespace std;
typedef long long ll;
typedef long double ld;
typedef pair<int, int> pii;
typedef pair<pii, int> piii;
typedef pair<ll, ll> pll;
#define debug(x) cerr<<#x<<'='<<(x)<<endl;
#define debugp(x) cerr<<#x<<"= {"<<(x.first)<<", "<<(x.second)<<"}"<<endl;
#define debug2(x, y) cerr<<"{"<<#x<<", "<<#y<<"} = {"<<(x)<<", "<<(y)<<"}"<<endl;
#define debugv(v) {cerr<<#v<<" : ";for (auto x:v) cerr<<x<<' ';cerr<<endl;}
#define all(x) x.begin(), x.end()
#define pb push_back
#define kill(x) return cout<<x<<'\n', 0;
const int inf=1000000010;
const ll INF=1000000000000001000LL;
const int mod=1000000007;
const int MAXN=300010, LOG=20;
ll ans;
int n, m, k, u, v, x, y, t, a, b;
int A[MAXN][3];
int main(){
ios_base::sync_with_stdio(false);cin.tie(0);cout.tie(0);
//freopen("input.txt", "r", stdin);
//freopen("output.txt", "w", stdout);
cin>>n;
for (int i=1; i<=2*n; i++){
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[x][y]++;
}
int dwn=0, up=0;
for (int i=1; i<=n; i++){
dwn+=A[i][1]-1;
up+=A[i][2]-1;
if (up>0 && dwn<0){
int d=min(-dwn, up);
dwn+=d;
up-=d;
ans+=d;
}
if (up<0 && dwn>0){
int d=min(dwn, -up);
dwn-=d;
up+=d;
ans+=d;
}
ans+=abs(dwn+up);
}
cout<<ans<<"\n";
return 0;
}
/*
2
1 1
1 1
2 2
2 2
*/
