#include <iostream>
#include <map>
#include <set>
#include <list>
#include <cmath>
#include <queue>
#include <stack>
#include <cstdio>
#include <string>
#include <vector>
#include <complex>
#include <cstdlib>
#include <cstring>
#include <numeric>
#include <sstream>
#include <algorithm>
#include <functional>
#include <limits.h>
#include <bitset>

#include <tuple>
#include <unordered_map>

#define mp make_pair
#define mt make_tuple
#define pb push_back
#define rep(i, n) for (int i = 0; i < (n); i++)

using namespace std;

typedef long long ll;
typedef unsigned long long ull;
typedef pair<int, int> pii;

const int INF = 1 << 29;
const double EPS = 1e-9;

const int dx[] = {1, 0, -1, 0}, dy[] = {0, -1, 0, 1};
int T,N;
vector<int> C;
vector<int> V;
int dp[20][10010][11];

int memo(int pos, int sum, int cnt, int value){
  if (pos == N){
    return 0;
  }
  if (sum > T)return 0;
  int &res = dp[pos][sum][cnt];
  if (res >= 0){
    return res;
  }
  res = 0;
  if (value > 0 and sum + C[pos] <= T){
    res = max(res, memo(pos, sum + C[pos], cnt + 1, value / 2) + value);
  }
  res = max(res, memo(pos + 1, sum, 0, V[pos + 1]));
  return res;
}

int main(){
  cin >> T;
  cin >> N;
  C.resize(N);
  V.resize(N);
  for (int i = 0; i < N; i++){
    cin >> C[i];
  }
  C.push_back(-1);
  for (int i = 0; i < N; i++){
    cin >> V[i];
  }
  V.push_back(-1);
  memset(dp, -1, sizeof(dp));
  cout << memo(0, 0, 0, V[0]) << endl;
}