#include<bits/stdc++.h>
using namespace std;
using ll = long long;

template<class T>bool chmax(T &a, const T &b) { if (a<b) { a=b; return 1; } return 0; }
template<class T>bool chmin(T &a, const T &b) { if (b<a) { a=b; return 1; } return 0; }

#define FOR(i,a,b) for(ll i=(a);i<(b);++i)
#define ALL(v) (v).begin(), (v).end()
#define p(s) cout<<(s)<<endl
#define p2(s, t) cout << (s) << " " << (t) << endl
#define br() p("")
#define pn(s) cout << (#s) << " " << (s) << endl
#define p_yes() p("YES")
#define p_no() p("NO")

const ll mod = 1e9 + 7;
const ll inf = 1e18;

void vprint(vector<ll> A){
    ll L = A.size();
    FOR(i, 0, L){
        if(i) cout << ' ';
        cout << A[i];
    }
    cout << endl;
}

int main(){
    cin.tie(0);
    ios::sync_with_stdio(false);

    // input
    ll N;
    cin >> N;

    vector<ll> P(4);
    vector<ll> T(4);
    FOR(i, 0, 4){
        cin >> P.at(i);
    }
    FOR(i, 0, 4){
        cin >> T.at(i);
    }

    ll min_price = inf;
    FOR(i, 0, N/T[0]+2){
        FOR(j, 0, N/T[1]+2){
            FOR(k, 0, N/T[2]+2){
                FOR(l, 0, N/T[3]+2){
                    ll num = T[0]*i + T[1]*j + T[2]*k + T[3]*l;
                    if(num>=N){
                        ll price = P[0]*i + P[1]*j + P[2]*k + P[3]*l;
                        chmin(min_price, price);
                    }
                }
            }
        }
    }
    p(min_price);
    
    return 0;
}
