#include <algorithm>
#include <iostream>
#include <vector>

int main() {
    using namespace std;
    int t, n;
    cin >> t >> n;
    vector<int> C(n), V(n);
    for (auto &e : C) { cin >> e; }
    for (auto &e : V) { cin >> e; }
    vector<pair<int, int>> attractions;
    for (int i = 0; i < n; i++) {
        while (V[i] > 0) {
            attractions.emplace_back(C[i], V[i]);
            V[i] /= 2;
        }
    }

    n = attractions.size();
    vector dp(n + 1, vector<int>(t + 1, -1));
    dp[0][0] = 0;
    for (int i = 0; i < n; i++) {
        auto [c, v] = attractions[i];
        for (int j = 0; j < t + 1; j++) {
            if (dp[i][j] == -1) { continue; }
            dp[i + 1][j] = max(dp[i + 1][j], dp[i][j]);
            if (j + c <= t) {
                dp[i + 1][j + c] = max(dp[i + 1][j + c], dp[i][j] + v);
            }
        }
    }
    int ans = 0;
    for (int j = 0; j < t + 1; j++) {
        ans = max(ans, dp[n][j]);
    }
    cout << ans << endl;
}