#include <iostream>
#include <vector>
#include <map>
#include <algorithm>
using namespace std;

#define REP(i,s,e) for (i = s; i <= e; i++)
#define rep(i,n) REP (i,0,(int)(n)-1)
#define RREP(i,s,e) for (i = s; i >= e; i--)
#define rrep(i,n) RREP (i,(int)(n)-1,0)
#define INF (int)1e8
#define MOD (int)(1e9+7)

typedef long long ll;

int dp[136][10001];

int main(void) {
    int i, j, k, t, n;
    int c[15], v[15][10] {};
    cin >> t >> n;
    rep (i,n) cin >> c[i];
    rep (i,n) {
        int x;
        cin >> x;
        for (j = 1; j <= 9; j++, x/=2)
            v[i][j] = x;
    }
    rep (i,n) REP (j,1,9) rep (k,t+1) {
        if (c[i]+k <= t)
            dp[i*9+j][c[i]+k] = dp[i*9+j-1][k]+v[i][j];
        dp[i*9+j][k] = max(dp[i*9+j][k],dp[i*9+j-1][k]);
    }
    cout << dp[n*9][t] << endl;
    return 0;
}