#include <bits/stdc++.h>

#define sz(x)  (int)x.size()
#define bigint __int128
#define el '\n'
#define ll long long
#define int long long
#define ld long double
using namespace std;
const int N = 1002, M = 1e5 + 10;

void acc() {
    int k, r;
    cin >> k >> r;
    int a[k];
    for (int i = 0; i < k; ++i) {
        cin >> a[i];
    }
    int ans = 0;
    for (int i = 0; i < r; ++i) {
        int mn = 1e18;
        for (int j = 0; j < k; ++j) {
            int f;
            cin >> f;
            mn = min(mn, a[j] / f);
        }
        int f;
        cin >> f;
        ans = max(ans, mn * f);
    }
    cout << ans;
}

signed main() {
    cout.tie(0);
    cin.tie(0);
    ios_base::sync_with_stdio(0);
    int t = 1;
    // cin >> t;
    while (t--)acc();
}