#include<stdio.h>
int main() {
	int n;
	int A, a, price1;
	int B, b, price2;
	int C, c, price3;
	int min = 100000, price;
	//小写abc表示种类编号，大写表示对应的盒数> <

	scanf("%d", &n);
	scanf("%d %d", &a, &price1);
	scanf("%d %d", &b, &price2);
	scanf("%d %d", &c, &price3);

	for (A = 0; A < n / a + 1; A++) {

		for (B = 0; B < n / b + 1; B++) {

			for (C = 0; C < n / c + 1; c++);

			if (A * a + B * b + C * c >= n) {
				price = A * price1 + B * price2 + C * price3;
				if (price < min) {
					min = price;
				}
			}
		}
		printf("%d", min);
	}