using System;
using System.Linq;

public class Program
{
    public static void Main() {
		int t = int.Parse(Console.ReadLine());
        int n = int.Parse(Console.ReadLine());
        int[] c = Console.ReadLine().Split(' ').Select(element => int.Parse(element)).ToArray();
        int[] v = Console.ReadLine().Split(' ').Select(element => int.Parse(element)).ToArray();		
		solve(t, c, v);
	}

    private static void solve(int t, int[] c, int[] v) {
		int[] dp = new int[t+1];
		
		for(int i=0;i<c.Length;i++)
        {
			int current = v[i];
		    while(current>0)
            {
				for(int j=dp.Length-1;j>=c[i];j--)
                {
					dp[j] = Math.Max(dp[j], dp[j-c[i]]+current);
				}
				current /= 2;
			}
		}		
		Console.WriteLine(dp[t]);
	}
}