#include <cstdio>
#include <stdio.h>
#include <stdbool.h>
#include <iostream>
#include <map>
#include <vector>
#include <climits>
#include <stack>
#include <string>
#include <queue>
#include <algorithm>
#include <set>
#include <unordered_set>
#include <unordered_map>
#include <cmath>
#include <cctype>
#include <bitset>
#include <iomanip>
#include <cstring>
#include <numeric>
#include <cassert>
using namespace std;
#define int long long
#define pii pair<int, int>
#define mp make_pair
#define pb push_back
#define fi first
#define se second
int32_t main(){
ios_base::sync_with_stdio(0);
cin.tie(0);
cout.tie(0);
int n, ans=0;
cin>>n;
vector<pii> top, down;
for (int i=0, a, b; i<2*n; ++i){
cin>>a>>b;
if (b>=2)down.pb(mp(a, b));
else top.pb(mp(a, b));
}
sort(top.begin(), top.end());
sort(down.begin(), down.end());
if (top.size()>down.size()){
for (int i=1; i<=n; ++i)ans+=abs(top[i-1].se-1)+abs(top[i-1].fi-i);
for (int i=n; i<top.size(); ++i)down.pb(top[i]);
sort(down.begin(), down.end());
for (int i=1; i<=n; ++i)ans+=abs(down[i-1].se-2)+abs(down[i-1].fi-i);
}
else{
for (int i=1; i<=n; ++i)ans+=abs(down[i-1].se-1)+abs(down[i-1].fi-i);
for (int i=n; i<down.size(); ++i)top.pb(down[i]);
sort(top.begin(), top.end());
for (int i=1; i<=n; ++i)ans+=abs(top[i-1].se-2)+abs(top[i-1].fi-i);
}
cout<<ans;
}
