import std.algorithm, std.array, std.container, std.range, std.bitmanip;
import std.numeric, std.math, std.bigint, std.random, core.bitop;
import std.string, std.conv, std.stdio, std.typecons;

void main()
{
  auto t = readln.chomp.to!int;
  auto n = readln.chomp.to!size_t;
  auto ci = readln.split.map!(to!int).array;
  auto vi = readln.split.map!(to!int).array;

  foreach (i; 0..n) {
    for (auto v = vi[i] / 2; v > 0; v /= 2) {
      ci ~= ci[i];
      vi ~= v;
    }
  }
  n = ci.length;

  auto memo = new int[](t + 1);
  foreach (i; 0..n) {
    auto c = ci[i], v = vi[i];
    foreach_reverse (j; c..t + 1)
      memo[j] = max(memo[j], memo[j - c] + v);
  }

  writeln(memo.reduce!(max));
}