#include <iostream>
#include <vector>
#include <cstdio>
#include <cstring>
using namespace std;
#define REP(i, n)           for(int(i)=0;(i)<(n);++(i))

int T, N, C[16], V;
int dp[160][10010];
int main(){
    cin >> T >> N;
    REP(i,N) cin >> C[i];
    vector<pair<int,int> >v;
    REP(i,N){
        cin >> V;
        while(V){
            v.push_back(make_pair(V,C[i]));
            V /= 2;
        }
    }

    memset(dp, -1, sizeof(dp));
    dp[0][0] = 0;

    int s = v.size();
    int maxv = 0;
    REP(i,s){
        int k = v[i].first, c = v[i].second;
        REP(j,T){
            if(dp[i][j] < 0) continue;
            if(j + c <= T){
                dp[i+1][j+c] = max(dp[i+1][j+c], dp[i][j] + k);
            }
            dp[i+1][j] = max(dp[i+1][j], dp[i][j]);
        }
    }
    REP(j,T+1) maxv = max(maxv, dp[s][j]);
    cout << maxv << endl;
    return 0;
}