# include <stdio.h>
# include <bits/stdc++.h>
using namespace std;
const pair < int , int > DD[] = {{1,0},{1,1},{0,1},{-1,1},{-1,0},{-1,-1},{0,-1},{1,-1}};
# define fi cin
# define fo cout
# define x first
# define y second
# define ll long long
# define IOS ios_base :: sync_with_stdio(0);cin.tie(0)
# define p(v) cerr << #v << " = " << v << '\n'
# define p2(v) cerr << #v << " = " << (complex < int > (v.x,v.y)) << '\n'
# define vi vector < int >
# define vl vector < ll >
# define pii pair < int , int >
# define mp make_pair
# define db long double
# define pb push_back
# define pdd pair < db , db >
# define CF
inline int readChar();
template <class T = int> inline T readInt();
template <class T> inline void writeInt( T x, char end = 0 );
inline void writeChar( int x );
inline void writeWord( const char *s );

/** Read */

static const int buf_size = 4096;

inline int getChar() {
    static char buf[buf_size];
    static int len = 0, pos = 0;
    if (pos == len)
        pos = 0, len = fread(buf, 1, buf_size, stdin);
    if (pos == len)
        return -1;
    return buf[pos++];
}

inline int readChar() {
    int c = getChar();
    while (c <= 32)
        c = getChar();
    return c;
}

template <class T>
inline T readInt() {
    int s = 1, c = readChar();
    T x = 0;
    if (c == '-')
        s = -1, c = getChar();
    while ('0' <= c && c <= '9')
        x = x * 10 + c - '0', c = getChar();
    return s == 1 ? x : -x;
}

/** Write */

static int write_pos = 0;
static char write_buf[buf_size];

inline void writeChar( int x ) {
    if (write_pos == buf_size)
        fwrite(write_buf, 1, buf_size, stdout), write_pos = 0;
    write_buf[write_pos++] = x;
}

template <class T>
inline void writeInt( T x, char end ) {
    if (x < 0)
        writeChar('-'), x = -x;

    char s[24];
    int n = 0;
    while (x || !n)
        s[n++] = '0' + x % 10, x /= 10;
    while (n--)
        writeChar(s[n]);
    if (end)
        writeChar(end);
}

inline void writeWord( const char *s ) {
    while (*s)
        writeChar(*s++);
}

struct Flusher {
    ~Flusher() {
        if (write_pos)
            fwrite(write_buf, 1, write_pos, stdout), write_pos = 0;
    }
} flusher;

int main(void)
{
    #ifdef CF
    #endif // CF
    srand(time(0));
    fo << fixed << setprecision(7);
    cerr << fixed << setprecision(7);
    int n,m;
    n = readInt();
    m = readInt();
    static ll dist[1 << 20];
    for (int i = 1;i < n;++i)
        dist[i] = readInt();
    static int s[5555][222];
    for (int i = 1;i <= n;++i)
        for (int j = 1;j <= m;++j)
            s[i][j] = readInt();
    ll ans = 0;
    static ll D[5555][5555];
    auto add = [&](int x1,int y1,int x2,int y2,ll v)
    {
        D[x1][y1] += v;
        D[x1][y2 + 1] -= v;
        D[x2 + 1][y1] -= v;
        D[x2 + 1][y2 + 1] += v;
    };
    for (int k = 1;k <= m;++k)
    {
        vi ss(n + 5);
        for (int i = 1;i <= n;++i)
            ss[i] = s[i][k];
        vi v = ss;
        sort(v.begin(),v.end());
        v.resize(unique(v.begin(),v.end()) - v.begin());
        reverse(v.begin(),v.end());
        static vi who[5555];
        for (int i = 1;i <= n;++i)
            who[i].clear();
        for (int i = 1;i <= n;++i)
            who[lower_bound(v.begin(),v.end(),ss[i],greater < int > ()) - v.begin() + 1].pb(i);
        set < int > used;
        used.insert(0);
        used.insert(n + 1);
        int sz = v.size();
        for (int i = 1;i <= sz;++i)
        {
            for (auto it : who[i])
            {
                auto high = used.lower_bound(it);
                auto low = high;
                --low;
                const int L = *low + 1;
                const int R = *high - 1;
                add(L,it,it,R,v[i - 1]);
                used.insert(it);
            }
        }
    }
    for (int i = 1;i <= n;++i)
        for (int j = 1;j <= n;++j)
            D[i][j] += D[i - 1][j] + D[i][j - 1] - D[i - 1][j - 1];
    for (int i = 2;i < n;++i)
        dist[i] += dist[i - 1];
    for (int i = 1;i <= n;++i)
        for (int j = i;j <= n;++j)
            ans = max(ans,D[i][j] - (dist[j - 1] - dist[i - 1]));
    fo << ans << '\n';
    cerr << "Time elapsed :" << clock() * 1000.0 / CLOCKS_PER_SEC << " ms" << '\n';
    return 0;
}


Measured memory_bytes: 220416