#include <iostream>
#include <string>
#include <vector>
#include <algorithm>
using namespace std;

int memo[150][10010] = {};

int CalcMaxValue(const vector<pair<int, int>>& attractions, int index, int t) {
	if (t == 0) return 0;
	if (index >= attractions.size()) return 0;

	if (memo[index][t] == 0) {
		int cost = attractions[index].first;
		int value = attractions[index].second;
		if (t - cost >= 0) {
			memo[index][t] = max(
				value + CalcMaxValue(attractions, index + 1, t - cost),
				CalcMaxValue(attractions, index + 1, t));
		}
		else {
			memo[index][t] = CalcMaxValue(attractions, index + 1, t);
		}
	}

	return memo[index][t];
}

int main() {
	int t, n;
	cin >> t >> n;

	int costs[20];
	for (int i = 0; i < n; i++) {
		cin >> costs[i];
	}

	vector<pair<int, int>> attractions;
	for (int i = 0; i < n; i++) {
		int value;
		cin >> value;
		while (value > 0) {
			attractions.push_back(pair<int, int>(costs[i], value));
			value /= 2;
		}
	}

	cout << CalcMaxValue(attractions, 0, t) << endl;
	
	return 0;
}