import java.util.Scanner;

public class Main {
	public static void main(String[] args) {
		Main p = new Main();
	}

	public Main() {
		Scanner sc = new Scanner(System.in);
		int t = sc.nextInt();
		int n = sc.nextInt();
		int[] c = new int[n];
		int[] v = new int[n];
		for(int i=0;i<n;i++)
			c[i] = sc.nextInt();
		
		for(int i=0;i<n;i++)
			v[i] = sc.nextInt();
		
		solve(t, c, v);
	}

	private void solve(int t, int[] c, int[] v) {
		int[] dp = new int[t+1];
		
		for(int i=0;i<c.length;i++){
			int cur = v[i];
			int count = 1;
			while(cur>0){
				for(int j=dp.length-1;j>=c[i]*count;j--){
					dp[j] = Math.max(dp[j], dp[j-c[i]]+cur);
				}
				cur /= 2;
			}
		}
		
		System.out.println(dp[t]);
	}
}