#include <bits/stdc++.h>
#define rep(i,n) for(int i=0;i<n;i++)
//#define int long long
using namespace std;

int T, N;
int c[15], v[15];
int newN;
int newc[135], newv[135];

int rec(int i, int t)
{
	int res;
	
	if (i == newN)
	{
		res = 0;
	}
	else if (t < newc[i])
	{
		res = rec(i + 1, t);
	}
	else
	{
		res = max(rec(i + 1, t), rec(i + 1, t - newc[i]) + newv[i]);
	}

	return res;
}

signed main()
{
	cin >> T;
	cin >> N;
	rep(i,N) cin >> c[i];
	rep(i,N) cin >> v[i];

	newN = 0;
	rep(i,N)
	{
		while (v[i] > 0)
		{
			newc[newN] = c[i];
			newv[newN] = v[i];
			v[i] /= 2;
			newN++;
		}
	}

	/*
	printf("newN = %d\n", newN);
	rep(i,newN) printf("(%d, %d)\n", newc[i], newv[i]);
	*/

	cout << rec(0, T) << endl;
}