#include <iostream>
using namespace std;
int main() {
    int n;
    cin >> n;
    int a1, b1, a2, b2, a3, b3;
    cin>>a1>>b1>>a2>>b2>>a3>>b3;
    int x1 = (n + a1 - 1) /a1 * b1;
    int y2 = (n + a2 - 1) /a2 * b2;
    int z3 = (n + a3 - 1) /a3 * b3;
    int mC = min(x1, min(y2, z3));
    cout << mC << endl;
    return 0;
}

ok 如此的easy 宝子们能看懂吧