#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using vi  = vector<int>; using vb  = vector<bool>; using vd  = vector<double>; using vl  = vector<ll>;
using vvi = vector<vi>;  using vvb = vector<vb>;   using vvd = vector<vd>;     using vvl = vector<vl>;

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

int main() {
	ll t, n;
	cin >> t >> n;
	vl _c(n); REP(i, n) cin >> _c[i];
	vl _v(n); REP(i, n) cin >> _v[i];
	
	vl c, v;
	REP(i, n) while(_v[i]>0){
		c.push_back(_c[i]);
		v.push_back(_v[i]);
		_v[i] /= 2;
	}

	vvl dp(t + 1, vl(v.size(), -1)); // dp[t+1][v.size()]
	dp[0][0] = 0;
	if (c[0] <= t) dp[c[0]][0] = v[0];
 	FOR(i, 0, v.size()-1) REP(j, t + 1) if(dp[j][i]!=-1){
		if (t >= j + c[i + 1]) dp[j + c[i + 1]][i + 1] = dp[j][i] + v[i + 1];
		dp[j][i + 1] = max(dp[j][i+1], dp[j][i]);
	}

	ll ans = 0;
	REP(i, t + 1) ans = max(ans, dp[i][v.size() - 1]);
	cout << ans << endl;
	return 0;
}