TollGate/Samsung

/*
TESTED AND VERIFIED
*/

#include<iostream>
using namespace std;

int n;
int cost[25];
int mens[25];

int ans;

void solve(int index, int one, int two, int three, int total){

    // optimization
    if(total > ans)return;

    int menAvailable = one + two + three;

    // base case
    if(index == n-1){
        if(menAvailable >= mens[n-1])
        ans = min(ans, total);
        else
        ans = min(ans, total + cost[n-1]);
        return;
    }

    // recursive case
    // hire the men
    solve(index + 1, one + mens[index], two, three, total + 2*cost[index]);
    //pay the cost
    solve(index + 1, one, two, three, total + cost[index]);
    // fight the men
    if(menAvailable >= mens[index]){
        if(two + three < mens[index])one = menAvailable - mens[index];
        if(three < mens[index])two = (two + three <= mens[index]) ? 0 : two - mens[index] + three;
        solve(index + 1, 0, one, two, total);
    }

}

int main(){

    cin>>n;

    for(int i = 0; i<n; i++)
    cin>>mens[i]>>cost[i];

    ans = 1000000;

    solve(0,0,0,0,0);
    cout<<ans<<endl;
    return 0;
}