#include<iostream>
#include<algorithm>


using namespace std;
int dp[100001];
int memo[100001][15];
int c[15];
int v[15];
int main(void){
	int T;
	int N;
	cin >> T >> N;
	for (int i = 0; i < N; i++){
		cin >> c[i];
	}
	for (int i = 0; i < N; i++){
		cin >> v[i];
		memo[0][i] = v[i];
	}
	for (int i = 0; i < T; i++){
		for (int j = 0; j < N; j++){
			if (i + c[j] <= T&&dp[i + c[j]] < dp[i] + memo[i][j]){
				dp[i + c[j]] = dp[i] + memo[i][j];
				for (int k = 0; k < N; k++){
					memo[i + c[j]][k] = memo[i][k];
				}
				memo[i + c[j]][j] /= 2;
			}
		}
	}
	
	int res = 0;
	for (int i = 0; i <= T; i++){
		res = max(dp[i], res);
	}
	cout << res << endl;
}