#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++)
		{
			if(j >= 1)
			{
				if(dp[i][j] < dp[i - 1][j])
				{
					dp[i][j] = dp[i - 1][j];
					dp_cou[i][j] = 0;
				}
			}
			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);
			}
			result = max(result , dp[i][j]);
		}
	}


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