#include<bits/stdc++.h>

using namespace std;

typedef struct
{   
    int up_node_cost = INT_MAX;
    int low_node_cost = INT_MAX;
    // int up_node_y = INT_MAX;
    // int low_node_y = INT_MAX;
}node;


void print_v(vector<int> v){
    for(int i = 0; i < v.size();i++){
        cout << v[i] << " ";
    }
    cout << endl;
}


int main(){
    int n;
    cin >> n;
    map<int,int> check_x;
    map<int, pair<int,int> > mp; // mp[X].first = min Y of X, mp[X].second = max Y of X
    vector<int> xses;

    map<int, node> columns;




    for(int i = 0; i < n; i++){
        int x,y;
        cin >> x >> y;
        if(check_x[x] == 0){
            mp[x].first = y;
            mp[x].second = y;
            xses.push_back(x);
            check_x[x] =1;
        }
        else{
            mp[x].first = min(mp[x].first, y);
            mp[x].second = max(mp[x].second, y);
        }
        // cout << x << " " << mp[x].first << " " << mp[x].second << endl;
        // v.push_back(make_pair(x,y));
    }
    // sort(v.begin(), v.end());
    sort(xses.begin(), xses.end());
    // print_v(xses);

    for(int i = 0; i < xses.size(); i++){
        // print_v(xses);
        int x = xses[i];


        // cout << "mp[x].first: " << mp[x].first << " \nmp[x].second: "  << mp[x].second << endl;

        if( i == 0) {
            columns[x].low_node_cost = abs(mp[x].first - mp[x].second);
            columns[x].up_node_cost = abs(mp[x].first - mp[x].second);
            
        }
        else{
            int prev_x = xses[i-1];
            // print_v(xses);
            int sum = abs(prev_x - x);

            int sum1 = sum + abs(mp[prev_x].first - mp[x].first); // down to down
            int sum3 = sum + abs(mp[prev_x].second - mp[x].first); // up to down

            int sum2 = sum + abs(mp[prev_x].first - mp[x].second); // down to up
            int sum4 = sum + abs(mp[prev_x].second - mp[x].second); // up to up 

            // cout << "prev_x: " << prev_x << "\nx: " << x << "\ni: " << i << endl;
            // cout << sum1 << " " << sum2 << " " << sum3  << " " << sum4 << endl;

            int sum_down = min(sum1,sum3);
            int sum_up = min(sum2,sum4);

            

            columns[x].low_node_cost = min(columns[x].low_node_cost,sum_down) + columns[prev_x].low_node_cost + abs(mp[x].first - mp[x].second);
            columns[x].up_node_cost = min(columns[x].up_node_cost,sum_up) + columns[prev_x].up_node_cost + abs(mp[x].first - mp[x].second);
            if(mp[x].first == mp[x].second){
                columns[x].low_node_cost = min(columns[x].low_node_cost, columns[x].up_node_cost);
                columns[x].up_node_cost = min(columns[x].low_node_cost, columns[x].up_node_cost);
            }

            swap(columns[x].low_node_cost,columns[x].up_node_cost);

            // cout << min(columns[x].low_node_cost,sum_down) + columns[prev_x].low_node_cost << endl;
            // cout << min(columns[x].up_node_cost,sum_up) + columns[prev_x].up_node_cost << endl;
            
        }
        // cout << "x: " << x << endl;
        // cout << "columns[x].low_node_cost: " << columns[x].low_node_cost << "\ncolumns[x].up_node_cost: " << columns[x].up_node_cost << endl;
        // cout << endl;
        
    }
    cout << min(columns[xses[xses.size()-1]].low_node_cost,columns[xses[xses.size()-1]].up_node_cost) << endl;
}