#include <bits/stdc++.h>

using namespace std;
typedef long long ll;
typedef pair<ll, ll> p_ll;

template<class T>
void debug(T itr1, T itr2) { auto now = itr1; while(now<itr2) { cout << *now << " "; now++; } cout << endl; }
#define repr(i,from,to) for (int i=(int)from; i<(int)to; i++)
#define all(vec) vec.begin(), vec.end()
#define rep(i,N) repr(i,0,N)
#define per(i,N) for (int i=(int)N-1; i>=0; i--)

const ll MOD = pow(10,9)+7;
const ll LLINF = pow(2,61)-1;
const int INF = pow(2,30)-1;

vector<ll> fac;
void c_fac(int x=pow(10,6)+10) { fac.resize(x,true); rep(i,x) fac[i] = i ? (fac[i-1]*i)%MOD : 1; }
ll inv(ll a, ll m=MOD) { ll b = m, x = 1, y = 0; while (b!=0) { int d = a/b; a -= b*d; swap(a,b); x -= y*d; swap(x,y); } return (x+m)%m; }
ll nck(ll n, ll k) { return fac[n]*inv(fac[k]*fac[n-k]%MOD)%MOD; }
ll gcd(ll a, ll b) { if (a<b) swap(a,b); return b==0 ? a : gcd(b, a%b); }
ll lcm(ll a, ll b) { return a/gcd(a,b)*b; }

struct attraction { ll c, v; };

int main() {
  int T, N; cin >> T >> N;
  ll c[N]; rep(i,N) cin >> c[i];
  ll v[N]; rep(i,N) cin >> v[i];

  vector<attraction> a;
  rep(i,N) {
    while(v[i]) {
      a.push_back({c[i],v[i]});
      v[i] /= 2;
    }
  }
  // for (auto x: a) cout << x.c << "->" << x.v << " " << endl;

  ll l = a.size();
  ll dp[l+1][T+1] = {};
  rep(i,l) rep(j,T+1) {
    dp[i+1][j] = max(dp[i+1][j], dp[i][j]);
    if (j+a[i].c<=T) {
      dp[i+1][j+a[i].c] = max(dp[i+1][j+a[i].c], dp[i][j]+a[i].v);
    }
  }
  // rep(i,l+1) debug(dp[i],dp[i]+(T+1));

  ll result = dp[l][T];
  cout << result << endl;
  return 0;
}