//#pragma comment(linker, "/stack:200000000")
//#pragma GCC optimize("Ofast")
//#pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,tune=native")
//#pragma GCC optimize("unroll-loops")
  
#include <iostream>
#include <stdlib.h>
#include <cmath>
#include <algorithm>
#include <vector>
#include <queue>
#include <deque>
#include <set>
#include <map>
#include <unordered_map>
#include <unordered_set>
#include <random>
#include <assert.h>
#include <memory.h>
#include <time.h>
#include <bitset>
 
#define uint unsigned int
#define ll long long
#define ull unsigned long long
#define ld long double
#define rep(i, l, r) for (int i = (l); i < (r); i++)
#define repb(i, r, l) for (int i = (r); i > (l); i--)
#define sz(a) (int)a.size()
#define fi first
#define se second
#define mp(a, b) make_pair(a, b)
#define rank qwertyuio
#define next dfghjk
#define prev fhsgfhjf
#define plus fsghsf
#define minus ytryr
  
using namespace std;
  
inline bool setmin(int &x, int y) { return (y < x) ? x = y, 1 : 0; }
inline bool setmax(int &x, int y) { return (y > x) ? x = y, 1 : 0; }
inline bool setmin(ll &x, ll y) { return (y < x) ? x = y, 1 : 0; }
inline bool setmax(ll &x, ll y) { return (y > x) ? x = y, 1 : 0; }
  
const int N = 5000;
const int inf = (int)1e9 + 1;
const ll big = (ll)1e18 + 1;
const int P = 239;
const int P1 = 31;
const int P2 = 57;
const int MOD = (int)1e9 + 7;
const int MOD1 = (int)1e9 + 9;
const int MOD2 = 998244353;
const ld eps = 1e-12;
const double pi = atan2(0, -1);
const int ABC = 26;

int cnt_v;
ll tree[N * 4];
ll add[N * 4];

void build(int n, ll *a) {
    cnt_v = 1;
    while (cnt_v < n) {
        cnt_v <<= 1;
    }
    rep(i, 0, n) {
        tree[cnt_v - 1 + i] = a[i];
    }
    repb(i, cnt_v - 2, -1) {
        tree[i] = max(tree[i * 2 + 1], tree[i * 2 + 2]);
    }
}

void push(int x) {
    tree[x * 2 + 1] += add[x];
    add[x * 2 + 1] += add[x];
    tree[x * 2 + 2] += add[x];
    add[x * 2 + 2] += add[x];
    add[x] = 0;
}

void upd(int x, int lx, int rx, int l, int r, ll v) {
    if (lx >= r || l >= rx) {
        return;
    } else if (lx >= l && rx <= r) {
        tree[x] += v;
        add[x] += v;
    } else {
        push(x);
        upd(x * 2 + 1, lx, (lx + rx) / 2, l, r, v);
        upd(x * 2 + 2, (lx + rx) / 2, rx, l, r, v);
        tree[x] = max(tree[x * 2 + 1], tree[x * 2 + 2]);
    }
}

ll get(int x, int lx, int rx, int l, int r) {
    if (lx >= r || l >= rx) {
        return -big;
    } else if (lx >= l && rx <= r) {
        return tree[x];
    } else {
        push(x);
        return max(get(x * 2 + 1, lx, (lx + rx) / 2, l, r), get(x * 2 + 2, (lx + rx) / 2, rx, l, r));
    }
}

ll d[N];
int a[N][200];

int main()
{
    //freopen("a.in", "r", stdin);
    //freopen("a.out", "w", stdout);
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    cout.precision(20);
    cout << fixed;
    //ll TL = 10.95 * CLOCKS_PER_SEC;
    //clock_t time = clock();
    int n, m;
    cin >> n >> m;
    d[0] = 0;
    rep(i, 1, n) {
        cin >> d[i];
        d[i] += d[i - 1];
    }
    build(n, d);
    vector<pair<int, int> > st[m];
    rep(i, 0, m) {
        st[i].push_back(mp(inf, -1));
    }
    ll ans = -big;
    rep(i, 0, n) {
        rep(j, 0, m) {
            int x;
            cin >> x;
            int pos = i - 1;
            while (x >= st[j].back().fi) {
                ll del = x - st[j].back().fi;
                st[j].pop_back();
                upd(0, 0, cnt_v, st[j].back().se + 1, pos + 1, del);
                pos = st[j].back().se;
            }
            upd(0, 0, cnt_v, i, i + 1, x);
            st[j].push_back(mp(x, i));
        }
        setmax(ans, get(0, 0, cnt_v, 0, i + 1) - d[i]);
        //cout << get(0, 0, cnt_v, 0, i + 1) - d[i] << endl;
    }
    cout << ans << "\n";
    return 0;
}

Measured memory_bytes: 2560