#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
#define rep(i, n) for(ll i = 0, i##_len = (n); i < i##_len; i++)
#define reps(i, s, n) for(ll i = (s), i##_len = (n); i < i##_len; i++)
#define rrep(i, n) for(ll i = (n) - 1; i >= 0; i--)
#define rreps(i, e, n) for(ll i = (n) - 1; i >= (e); i--)
#define all(x) (x).begin(), (x).end()
#define rall(x) (x).rbegin(), (x).rend()
#define sz(x) ((ll)(x).size())
#define len(x) ((ll)(x).length())
#define endl "\n"

int main() {
    cin.tie(0);
    ios::sync_with_stdio(false);
    // ifstream in("input.txt");
    // cin.rdbuf(in.rdbuf());
    const ll inf = LONG_LONG_MIN / 2 - 1;
    ll t, n;
    cin >> t >> n;
    vector<ll> c(n), v(n);
    rep(i, n) cin >> c[i];
    rep(i, n) cin >> v[i];
    vector<ll> dp(t + 1, inf);
    dp[0] = 0;
    rep(i, n) {
        while(v[i] > 0) {
            rreps(j, c[i], t + 1) {
                dp[j] = max(dp[j], dp[j - c[i]] + v[i]);
            }
            v[i] /= 2;
        }
    }
    cout << *max_element(all(dp)) << endl;
    return 0;
}