#include<cstdio>
#include<vector>


using namespace std;


struct a_t
{
	int c, v;
};


vector<a_t> a;
vector<vector<int> > memo;


int max(int a, int b)
{
	if(a>b) return a;
	return b;
}


int max_u(int& m, int v)
{
	if(m<v)
	{
		m=v;
		return 1;
	}
	return 0;
}


int solve_r(int t, int v, int n)
{
	int ret;

	if(max_u(memo[n][t], v)==0) return memo[n][t];

	if(n<=0)
	{
		return memo[n][t]=v;
	}
	ret=solve_r(t, v, n-1);
	if(t>=a[n-1].c) max_u(ret, solve_r(t-a[n-1].c, v+a[n-1].v, n-1));
	return memo[n][t]=ret;
}


int solve(int t)
{
	memo.clear();
	memo.resize(a.size()+1);
	for(int i=memo.size()-1;i>=0;i--)
	{
		memo[i].resize(t+1, -1);
	}
	return solve_r(t, 0, a.size());
}


int main(void)
{
	int t, n, i, j;
	vector<int> c, v, f;

	while(scanf("%d%d", &t, &n)==2)
	{
		a.clear();
		c.resize(n);
		v.resize(n);
		for(i=0;i<n;i++) scanf("%d", &c[i]);
		for(i=0;i<n;i++) scanf("%d", &v[i]);

		for(i=0;i<n;i++)
		{
			for(j=0;v[i]>>j;j++)
			{
				a.push_back((a_t){c[i], v[i]>>j});
			}
		}
/*
		for(i=0;i<a.size();i++) printf("%d %d\n", a[i].c, a[i].v);
		printf("a.size()=%d\n", a.size());
*/
		printf("%d\n", solve(t));
	}

	return 0;
}