#include "bits/stdc++.h"
using namespace std;

typedef long long Int;
#define REP(i,n) for(int (i)=0;(i)<(int)(n);++(i))


int dp[10010];

int main() {
	int T, N;
	cin >> T >> N;
	vector<int> c, v;
	REP(i, N) { int x; cin >> x; c.push_back(x); }
	REP(i, N) { int x; cin >> x; v.push_back(x); }
	REP(i, N) {
		int x = v[i] / 2;
		while (x > 0) {
			v.push_back(x);
			c.push_back(c[i]);
			x /= 2;
		}
	}
	const int inf = 999999999;
	REP(i, T + 1) dp[i] = -inf;
	dp[0] = 0;

	REP(i, v.size()) {
		for (int t = T - c[i]; t >= 0; t--) {
			if (dp[t + c[i]] < dp[t] + v[i]) {
				dp[t + c[i]] = dp[t] + v[i];
			}
		}
	}

	
	cout << *max_element(dp, dp + T + 1) << endl;

}