#include<stdio.h>
int min(x, y, z)
{
	int Min;
	Min = x > y ? y : x;
	Min = Min > z ? z : Min;
}
int main(void)
{
	int n, p1, p2, p3, b1, b2, b3, m1, m2, m3, Min;
	scanf("%d", &n);
	scanf("%d %d", &p1, &b1);
	scanf("%d %d", &p2, &b2);
	scanf("%d %d", &p3, &b3);
	for (int i = 0;n > i*p1;)
	{
		i += 1;
		m1 = i * b1;
	}
	for (int i = 0;n > i * p2;)
	{
		i += 1;
		m2 = i * b2;
	}
	for (int i = 0;n > i * p3;)
	{
		i += 1;
		m3 = i * b3;
	}
	Min = min(m1, m2, m3);
	printf("%d", Min);
	return 0;
}