#include <bits/stdc++.h>
#define rep(i, a) for (int i = 0; i < (a); i++)
#define rep2(i, a, b) for (int i = (a); i < (b); i++)
#define repr(i, a) for (int i = (a) - 1; i >= 0; i--)
#define repr2(i, a, b) for (int i = (b) - 1; i >= (a); i--)
using namespace std;
typedef long long ll;
const ll inf = 1e9;
const ll mod = 1e9 + 7;

int T, N;
int c[15], v[15];
int V[15][20];

int dp[22][20202];

int main() {
	cin >> T >> N;
	rep (i, N) cin >> c[i];
	rep (i, N) cin >> v[i];

	rep (i, N) {
		rep (j, 20) {
			V[i][j] = v[i] >> j;	
		}
	}

	rep (i, 22) rep (j, 20202) dp[i][j] = -inf;
	dp[0][0] = 0;

	rep (i, N) {
		rep (j, T + 1) {
			int total = 0;
			dp[i + 1][j] = max(dp[i + 1][j], dp[i][j]);
			rep (k, 20) {
				total += V[i][k];
				dp[i + 1][j + c[i] * (k + 1)] = max(dp[i + 1][j + c[i] * (k + 1)], dp[i][j] + total);
			}
		}
	}

	int ans = -1;
	rep (j, T + 1) {
		ans = max(ans, dp[N][j]);
	}
	cout << ans << endl;

	return 0;
}