#include <stdio.h>
#include <bits/stdc++.h>
#include <atcoder/all>
using namespace atcoder;
using mint = modint998244353;
using namespace std;
#define rep(i,n) for (int i = 0; i < (n); ++i)
#define Inf 1000000

int main(){
	
	int T,N;
	cin>>T>>N;
	
	vector<int> c,v;
	{
		vector<int> x(N),y(N);
		rep(i,N)cin>>x[i];
		rep(i,N)cin>>y[i];
		rep(i,N){
			int a,b;
			a = x[i],b = y[i];
			while(b!=0){
				c.push_back(a);
				v.push_back(b);
				b>>=1;
			}
		}
	}
	vector dp(T+1,0);
	rep(i,c.size()){
		vector ndp(T+1,0);
		rep(j,T+1){
			ndp[j] = max(ndp[j],dp[j]);
			if(j+c[i]<=T){
				ndp[j+c[i]] = max(ndp[j+c[i]],dp[j] + v[i]);
			}
		}
		swap(dp,ndp);
	}
	int ans = 0;
	rep(i,T+1)ans = max(ans,dp[i]);
	cout<<ans<<endl;
	
	return 0;
}