import java.math.*;
import java.util.*;
 
public class Main {
	static int n;
	static int[] c;
	static int[] v;
	static int[] dp;
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int t=sc.nextInt();
        n = sc.nextInt();
        dp=new int[t+1];
        c=new int[n];
        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();
        }
        for(int i=0;i<n;i++){
        	int cur = v[i];
        	int count=1;
        	while(cur>0){
        		for(int j=t;j>=c[i]*count;j--){
        			dp[j]=Math.max(dp[j],dp[j-c[i]]+cur);
        		}
        		cur/=2;
        		count++;
        	}
        }

    	System.out.println(dp[t]);
    }
}