#include <iostream>
using namespace std;

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

    for (int i = 0; i < N; i++) {
        cin >> c[i];
    }
    for (int i = 0; i < N; i++) {
        cin >> v[i];
    }

    int satis[T+1] = {1};
    
    for (int i = 0; i < N; i++) {
        for (int j = T; j >= 0; j--) {
            if (satis[j]) {
                int s = v[i];
                int t = c[i];
                for (int k = j+t; (k <= T) && s; k+=t) {
                    satis[k] = max(satis[k], satis[k-t] + s);
                    s /= 2;
                }
            }
        }
    }

    int maxval = 0;
    for (int i = 0; i < T+1; i++) {
        maxval = max(maxval, satis[i]);
    }

    cout << maxval - 1 << endl;;
    
    return 0;
}