#include <iostream>
#include <string>
#include <cstdlib>
#include <vector>
#include <algorithm>
#include <queue>
#include <set>
#include <map>
using namespace std;

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

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

int dp[20][100010];

int dp_cou[20][10010];

vector<int> Cs;

vector<int> Vs;

int main()
{

    FOR(i, 0, 19)
    FOR(j, 0, 10009) dp[i][j] = -1000000000;
    dp[0][0] = 0;
    cin >> T >> N;

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

    int M = Cs.size();

    FOR(i, 0, M - 1)
    {
        FOR(j, 0, T)
        {
            if(j - Cs[i] >= 0)
            {
                dp[i + 1][j] = max(dp[i][j] , dp[i][j - Cs[i]] + Vs[i]);
            }
            else
            {
                dp[i + 1][j] = dp[i][j];
            }

            if(j > 0) dp[i + 1][j] = max(dp[i + 1][j],dp[i + 1][j - 1]);
        }
    }

    cout << dp[M][T] << endl;
    return 0;
}