#include <vector>
#include <list>
#include <map>
#include <set>
#include <deque>
#include <stack>
#include <queue>
#include <bitset>
#include <algorithm>
#include <functional>
#include <numeric>
#include <utility>
#include <sstream>
#include <iostream>
#include <iomanip>
#include <cstdio>
#include <cmath>
#include <cstdlib>
#include <cctype>
#include <string>
#include <cstring>
#include <ctime>

using namespace std;

inline int toInt(string s) {int v; istringstream sin(s);sin>>v;return v;}
template<class T> inline string toString(T x) {ostringstream sout;sout<<x;return sout.str();}

typedef vector<int> VI;
typedef vector<VI> VVI;
typedef vector<string> VS;
typedef pair<int, int> PII;
typedef long long LL;
typedef unsigned long long ULL;

#define FOR(i,a,b) for(int i=(a);i<(b);++i)
#define REP(i,n)  FOR(i,0,n)

#define MP make_pair
#define SZ(a) int((a).size())
#define EACH(i,c) for(auto i: c)
#define SORT(c) sort((c).begin(),(c).end())

#define ALL(a)  (a).begin(),(a).end()
#define RALL(a) (a).rbegin(), (a).rend()

const double EPS = 1e-10;
const double PI  = acos(-1.0);

#define dump(x)  cerr << #x << " = " << (x) << endl;
#define debug(x) cerr << #x << " = " << (x) << " (L" << __LINE__ << ")" << " " << __FILE__ << endl;

int main() {
	cin.tie(0);
	ios::sync_with_stdio(false);

	int T, N;
	cin >> T >> N;
	VI C(N), V(N);
	REP(i, N) cin >> C[i];
	REP(i, N) cin >> V[i];
	const int MAX = 1e9;
	vector<vector<pair<int, int> > > W(9, vector<pair<int, int> >(N, MP(0, 0)));
	REP(i, N) W[0][i] = MP(C[i], V[i]);
	REP(j, N) REP(i, 8){
		V[j] /= 2;
		W[i + 1][j] = MP(W[i][j].first +C[j], W[i][j].second + V[j]);
		if(V[j] == 0) break;
	}
	/*
	REP(i, 9){
		REP(j, N){
			cout << W[i][j].first << "/" << W[i][j].second << " ";
		}
		cout << endl;
	}
	*/

	VVI dp(N + 1, VI(T + 1, MAX));
	int ret = 0;
	REP(i, N + 1) dp[i][0] = 0;
	REP(i, N) REP(j, T){
		if(dp[i][j] == MAX) continue;
		REP(k, 9){
			if(j + W[k][i].first > T) break;
			dp[i + 1][j] = min(dp[i + 1][j], dp[i][j]);
			dp[i + 1][j + W[k][i].first] = min(dp[i + 1][j + W[k][i].first], dp[i][j] + W[k][i].second);
			ret = max(ret, dp[i + 1][j + W[k][i].first]);
		}
	}
	/*
	REP(i, N + 1){
		REP(j, T + 1){
			cout << dp[i][j] << " ";
		}
		cout << endl;
	}
	*/
	cout << ret << endl;
	return 0;
}