#pragma GCC optimize("Ofast")
#pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx")
#pragma GCC optimize("unroll-loops")
//#pragma warning(disable : 4996)

#ifdef _MSC_VER
#include <intrin.h>
#define __builtin_popcount __popcnt
#define __builtin_popcountll __popcnt64
#endif

#include <limits.h>
#include <math.h>
#include <time.h>

#include <algorithm>
#include <array>
#include <bitset>
#include <cassert>
#include <complex>
#include <cstdio>
#include <cstring>
#include <functional>
#include <iomanip>
#include <iostream>
#include <iterator>
#include <map>
#include <numeric>
#include <queue>
#include <random>
#include <set>
#include <stack>
#include <string>
#include <unordered_map>
#include <unordered_set>
#include <vector>

using namespace std;

#define REP(i, n) for (int i = 0; i < (n); ++i)
#define REPR(i, n) for (int i = n - 1; i >= 0; --i)
#define FOR(i, m, n) for (int i = m; i < n; ++i)
#define FORR(i, m, n) for (int i = m - 1; i >= n; --i)
#define SORT(v, n) sort(v, v + n);
#define VSORT(v) sort(v.begin(), v.end());
#define REVERSE(v, n) reverse(v, v + n);
#define VREVERSE(v) reverse(v.begin(), v.end())
#define ll long long
#define print(x) cout << (x) << '\n'
#define pe(x) cout << (x) << " "
#define DEBUG(x) cout << #x << ": " << x << endl
#define lb(v, n) lower_bound(v.begin(), v.end(), (n))
#define ub(v, n) upper_bound(v.begin(), v.end(), (n))
//#define int long long
//#define double long double
#define all(x) (x).begin(), (x).end()
#define print_space(v) REP(i, v.size()) cout << v[i] << ((i == v.size() - 1) ? "\n" : " ")
template <typename T1, typename T2> inline void chmin(T1& a, T2 b) {
    if (a > b) a = b;
}
template <typename T1, typename T2> inline void chmax(T1& a, T2 b) {
    if (a < b) a = b;
}
typedef pair<int, int> pii;
typedef pair<long long, long long> pll;
std::random_device rd;
std::mt19937 mt(rd());
constexpr ll MOD = 1e9 + 7;
constexpr int MAX = 500050;
const double pi = acos(-1);
constexpr double EPS = 1e-8;
constexpr ll LINF = 1e18 + 1;
constexpr int INF = 1e9 + 1;

template <typename T> struct SegmentTree {
    int n;
    T unit;
    vector<T> dat;
    function<T(T, T)> func;
    SegmentTree(const int N, T _unit, function<T(T, T)> _func) : unit(_unit), func(_func) {
        n = 1;
        //簡単のため、要素数を2のべき乗に
        while (n < N) n *= 2;
        dat.assign(2 * n, unit);
    }

    void update(int k, T a) {
        k += n - 1;  //葉の節点
        dat[k] = a;
        //上りながら更新
        while (k > 0) {
            k = (k - 1) / 2;
            dat[k] = func(dat[k * 2 + 1], dat[k * 2 + 2]);
        }
    }
    T _query(int a, int b, int k, int l, int r) {
        //[a,b)と[l,r)が交差していなければ、funcに影響を与えない値を返す
        if (r <= a || b <= l) return unit;
        //[a,b)が[l,r)を完全に含んでいれば、この節点の値
        if (a <= l && r <= b)
            return dat[k];
        else {
            T vl = _query(a, b, k * 2 + 1, l, (l + r) / 2);
            T vr = _query(a, b, k * 2 + 2, (l + r) / 2, r);
            return func(vl, vr);
        }
    }
    //[a,b)
    T query(int a, int b) { return _query(a, b, 0, 0, n); }
};
// auto f = [](int a, int b) {return a + b; };
// SegmentTree<int>seg(N,0,f);

int N, M;
vector<int> A;
vector<int> val[202];
vector<pii> vp[202];
ll sum[5050][5050];
ll cum[5050];
void solve() {
    cin >> N >> M;
    A.resize(N - 1);
    REP(i, N - 1) {
        cin >> A[i];
        cum[i + 1] = cum[i] + A[i];
    }
    REP(j, M) {
        val[j].resize(N);
        vp[j].resize(N);
    }
    REP(i, N) REP(j, M) {
        cin >> val[j][i];
        vp[j][i] = {val[j][i], i};
    }
    auto f = [](pii a, pii b) { return max(a, b); };
    vector<SegmentTree<pii>> seg(M, SegmentTree<pii>(N, {0, 0}, f));
    REP(j, M) {
        REP(i, N) { seg[j].update(i, vp[j][i]); }
    }
    REP(j, M) {
        // DEBUG(j);
        auto func = [&](auto f, int l, int r) -> void {
            if (l >= r) return;
            // DEBUG(l);
            // DEBUG(r);
            pii p = seg[j].query(l, r);
            int i = p.second;
            // DEBUG(i);
            int v = p.first;
            sum[l][i + 1] += v;
            sum[i + 1][r + 1] += v;
            sum[i + 1][i + 1] -= v;
            sum[l][r + 1] -= v;
            f(f, l, i);
            f(f, i + 1, r);
        };
        // print("a");
        func(func, 0, N);
        // print("b");
    }
    REP(i, N + 1) {
        REP(j, N + 1) {
            sum[i + 1][j] += sum[i][j];
            sum[i][j + 1] += sum[i][j];
            sum[i + 1][j + 1] -= sum[i][j];
        }
    }
    // REP(i, N + 1) {
    //     REP(j, N + 1) { cout << sum[i][j] << " "; }
    //     cout << endl;
    // }
    ll ans = 0;
    REP(l, N) {
        FOR(r, l + 1, N + 1) {
            ll res = -(cum[r - 1] - cum[l]);
            res += sum[l][r];
            chmax(ans, res);
        }
    }
    print(ans);
}

signed main() {
    cin.tie(0);
    ios::sync_with_stdio(false);
    // Eratosthenes();
    // VSORT(sosuu);
    // REP(_, 100)test();
    // cerr << "done" << endl;
    // int q;
    // cin >> q;
    // while (q--)
    solve();
}


Measured memory_bytes: 238908