#include <iostream>
#include <vector>

void solve() {
    int t, n;
    std::cin >> t >> n;

    std::vector<int> cs(n), vs(n);
    for (auto& c : cs) std::cin >> c;
    for (auto& v : vs) std::cin >> v;

    std::vector<std::pair<int, int>> ps;
    for (int i = 0; i < n; ++i) {
        int c = cs[i], v = vs[i];
        while (v > 0) {
            ps.emplace_back(c, v);
            v /= 2;
        }
    }

    std::vector<int> dp(t + 1, 0);
    for (auto [c, v] : ps) {
        for (int x = t; x >= c; --x) {
            dp[x] = std::max(dp[x], dp[x - c] + v);
        }
    }

    std::cout << dp[t] << "\n";
}

int main() {
    std::cin.tie(nullptr);
    std::ios::sync_with_stdio(false);

    solve();

    return 0;
}