#include <iostream>
#include <algorithm>
using namespace std;

int t, n;
int c[22], v[22], dp[10001][22];

int rec(int t, int idx){
  
  if(idx == n) return 0;
  if(dp[t][idx]) return dp[t][idx];
  
  int ret = 0, sum = 0, emacs = v[idx];
  ret = max( ret, rec( t, idx + 1));
  for(int i = t - c[idx]; i >= 0 && emacs != 0; i-=c[idx]){
    sum += emacs;
    emacs /= 2;
    ret = max(ret, rec(i, idx + 1) + sum);
  }
  return dp[t][idx] = ret;
}
	  
int main(){
  
  cin >> t >> n;
  for(int i = 0; i < n; i++) cin >> c[i];
  for(int i = 0; i < n; i++) cin >> v[i];
  
  cout << rec(t, 0) << endl;
}