#include <iostream>
#include <vector>
using namespace std;

#define FOR(i, s, e) for (int i = (s); i <= (e); i++)

int T;
int N;
int c[20];
int v[20];

vector<int> Vs[20];

int dp[20][20000];

int dp_cou[20][20000];
int main()
{
	cin >> T;
	cin >> N;

	FOR(i, 1, N)
	{
		cin >> c[i];
	}

	FOR(i, 1, N)
	{
		cin >> v[i];
		while (v[i] > 0)
		{
			Vs[i].push_back(v[i]);
			v[i] /= 2;
		}
		Vs[i].push_back(0);
	}

	int result = 0;

	for (int i = 1; i <= N; i++)
	{
		for (int j = 0; j <= T; j++)
		{
			dp[i][j] = max(dp[i][j] , dp[i - 1][j]);
			{
				if (j + c[i] <= T && dp[i][j + c[i]] < dp[i - 1][j] + Vs[i][0])
				{
					dp[i][j + c[i]] = dp[i - 1][j] + Vs[i][0];
					dp_cou[i][j + c[i]] += min(1, (int)Vs[i].size() - 1);
				}
			}
			
			if (j + c[i] <= T && dp[i][j + c[i]] < dp[i][j] + Vs[i][dp_cou[i][j]])
			{
				dp[i][j + c[i]] = dp[i][j] + Vs[i][dp_cou[i][j]];
				dp_cou[i][j + c[i]] += min(dp_cou[i][j] + 1, (int)Vs[i].size() - 1);
			}
			//cout << i << " " << j << "=" << dp[i][j] << endl;
			result = max(result, dp[i][j]);
		}
	}

	cout << result << endl;
	return 0;
}