#include <bits/stdc++.h>
#define fst first
#define snd second
#define pb push_back
#define SZ(x) (int)x.size()
#define ALL(x) x.begin(),x.end()
#define forn(i,a,b) for(int i = a; i<b; i++)
#define mset(a,v) memset(a,v,sizeof(a))
#define FIN ios::sync_with_stdio(0); cin.tie(0); cout.tie(0);
using namespace std;
typedef long long ll;
const int MAXN = 1000+5;
ll n;
ll dp[MAXN][MAXN];
vector<pair<ll,ll>> p;
ll f(ll x, ll y){
ll &res=dp[x][y];
if(res!=-1) return res;
if(x==2*n && y==n) return 0;
if(x==2*n) return 1000000000000000;
res=1000000000000000;
pair<ll,ll> p1 = {1+x-y,1};
pair<ll,ll> p2 = {1+y,2};
res=min(res,f(x+1,y+1)+abs(p[x].fst-p2.fst)+abs(p[x].snd-p2.snd));
res=min(res,f(x+1,y)+abs(p[x].fst-p1.fst)+abs(p[x].snd-p1.snd));
return res;
}
bool comp(const pair<ll,ll> &a, const pair<ll,ll> &b){
if(a.fst<b.fst) return true;
if(a.fst>b.fst) return false;
if(abs(a.snd-1)<abs(b.snd-1)) return true;
return false;
}
int main(){
cin>>n;
p.clear();
p.resize(2*n); forn(i,0,2*n) cin>>p[i].fst>>p[i].snd;
sort(ALL(p),comp);
mset(dp,-1);
ll res = f(0,0);
if(res>=1000000000000000){
cout<<-1<<'\n';
}else cout<<res<<'\n';
return 0;
}
