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

#undef _P
#define _P(...) (void)printf(__VA_ARGS__)
#define FORR(x,arr) for(auto&& x:arr)
#define FOR(i,a,b) for (int i = (a); i < (b); i++)
#define RFOR(i,a,b) for (int i = (b)-1; i >= (a); i--)
#define REP(i,n) for (int i = 0; i < (n); i++)
#define RREP(i,n) for (int i = (n)-1; i >= 0; i--)
#define ALL(x) (x).begin(), (x).end()
#define ITR(x,c) for(__typeof(c.begin()) x=c.begin();x!=c.end();x++)
#define RITR(x,c) for(__typeof(c.rbegin()) x=c.rbegin();x!=c.rend();x++)
#define BIT(n) (1LL<<(n))
#define SZ(x) ((int)(x).size())
typedef long long ll;
// -------------------------------------

int T, N;
vector<int> C;
vector<int> V;

template<class T> inline bool amax(T &a, const T &b) { if (a < b) { a = b; return 1; } return 0; }

int main() {
  scanf("%d\n%d", &T, &N);
  REP(i, N) {
    int c;
    scanf("%d", &c);
    C.push_back(c);
  }
  REP(i, N) {
    int v;
    scanf("%d", &v);
    V.push_back(v);
  }

  REP(i, N) {
    int v = V[i]/2;
    while (v) {
      C.push_back(C[i]);
      V.push_back(v);
      v /= 2;
    }
  }

  N = SZ(C);

  vector<int> dp(T+1);
  fill(ALL(dp), -1);
  dp[0] = 0;

  int ans = 0;
  REP(i, N) RREP(j, T) if (dp[j] >= 0) {
    if (j + C[i] <= T) {
      amax(dp[j + C[i]], dp[j] + V[i]);
      amax(ans, dp[j + C[i]]);
    }
  }

  cout << ans << endl;

  return 0;
}