import java.util.Scanner;

public class Main{
	public static void main(String[] args)
	{
		Scanner s=new Scanner(System.in);
		int n=s.nextInt();
		int[] a=new int[3];
		int[] p=new int[3];
		int[] sum=new int[3];
		int i;
		int min=Integer.MAX_VALUE;
		for(i=0;i<3;i++)
		{
			a[i]=s.nextInt();
			p[i]=s.nextInt();
		}
		for(i=0;i<3;i++)
		{
			if(n%a[i]!=0)
				sum[i]=(n/a[i]+1)*p[i];
			else
				sum[i]=(n/a[i])*p[i];
			if(sum[i]<min)
				min=sum[i];
		}
		System.out.println(min);			
	}
	
}