#include <bits/stdc++.h>

#define show(x) cout << #x << " = " << x << endl

using namespace std;
using ll = long long;
using pii = pair<int, int>;
using vi = vector<int>;

template <typename T>
ostream& operator<<(ostream& os, const vector<T>& v)
{
    os << "sz=" << v.size() << "\n[";
    for (const auto& p : v) {
        os << p << ",";
    }
    os << "]\n";
    return os;
}

template <typename S, typename T>
ostream& operator<<(ostream& os, const pair<S, T>& p)
{
    os << "(" << p.first << "," << p.second
       << ")";
    return os;
}


constexpr ll MOD = 1e9 + 7;

template <typename T>
constexpr T INF = numeric_limits<T>::max() / 100;

int main()
{
    int T, N;
    cin >> T >> N;
    vector<int> cost(N);
    vector<int> val(N);
    for (ll i = 0; i < N; i++) {
        cin >> cost[i];
    }
    for (ll i = 0; i < N; i++) {
        cin >> val[i];
    }
    for (ll i = 0; i < N; i++) {
        int v = val[i] / 2;
        while (v > 0) {
            cost.push_back(cost[i]);
            val.push_back(v);
            v /= 2;
        }
    }
    // show(val);
    // show(cost);
    const int size = cost.size();
    vector<vector<int>> dp(size + 1, vector<int>(T + 1, -1));  // i番目のアトラクションまでチェックして残り時間t の最大幸福
    dp[0][T] = 0;
    for (ll i = 1; i <= size; i++) {
        // show(dp);
        const int v = val[i - 1];
        const int tim = cost[i - 1];
        for (ll t = 0; t <= T; t++) {
            if (t + tim > T) {
                if (dp[i - 1][t] != -1) {
                    dp[i][t] = dp[i - 1][t];
                }
            } else {
                if (dp[i - 1][t + tim] != -1) {
                    dp[i][t] = max(dp[i][t], dp[i - 1][t + tim] + v);
                }
                if (dp[i - 1][t] != -1) {
                    dp[i][t] = max(dp[i][t], dp[i - 1][t]);
                }
            }
        }
    }
    // show(dp);
    int ans = 0;
    for (ll i = 0; i <= T; i++) {
        if (dp[size][i] != -1) {
            ans = max(ans, dp[size][i]);
        }
    }
    cout << ans << endl;

    return 0;
}