#include <iostream>
#include <algorithm>
#include <bitset>
#include <map>
#include <queue>
#include <set>
#include <stack>
#include <string>
#include <utility>
#include <vector>
#include <array>
#include <unordered_map>
#include <complex>
#include <deque>
#include <cassert>
#include <cmath>
#include <functional>
#include <iomanip>
#include <chrono>
#include <random>
#include <numeric>
#include <tuple>
#include <cstring>
using namespace std;

#define forr(x,arr) for(auto&& x:arr)
#define _overload3(_1,_2,_3,name,...) name
#define _rep2(i,n) _rep3(i,0,n)
#define _rep3(i,a,b) for(int i=int(a);i<int(b);++i)
#define rep(...) _overload3(__VA_ARGS__,_rep3,_rep2,)(__VA_ARGS__)
#define _rrep2(i,n) _rrep3(i,0,n)
#define _rrep3(i,a,b) for(int i=int(b)-1;i>=int(a);i--)
#define rrep(...) _overload3(__VA_ARGS__,_rrep3,_rrep2,)(__VA_ARGS__)
#define all(x) (x).begin(),(x).end()
#define bit(n) (1LL<<(n))
#define sz(x) ((int)(x).size())
#define TEN(n) ((ll)(1e##n))
#define fst first
#define snd second

string DBG_DLM(int &i){return(i++==0?"":", ");}
#define DBG_B(exp){int i=0;os<<"{";{exp;}os<<"}";return os;}
template<class T>ostream&operator<<(ostream&os,vector<T>v);
template<class T>ostream&operator<<(ostream&os,set<T>v);
template<class T>ostream&operator<<(ostream&os,queue<T>q);
template<class T>ostream&operator<<(ostream&os,priority_queue<T>q);
template<class T,class K>ostream&operator<<(ostream&os,pair<T,K>p);
template<class T,class K>ostream&operator<<(ostream&os,map<T,K>mp);
template<class T,class K>ostream&operator<<(ostream&os,unordered_map<T,K>mp);
template<int I,class TPL>void DBG(ostream&os,TPL t){}
template<int I,class TPL,class H,class...Ts>void DBG(ostream&os,TPL t){os<<(I==0?"":", ")<<get<I>(t);DBG<I+1,TPL,Ts...>(os,t);}
template<class T,class K>void DBG(ostream&os,pair<T,K>p,string delim){os<<"("<<p.first<<delim<<p.second<<")";}
template<class...Ts>ostream&operator<<(ostream&os,tuple<Ts...>t){os<<"(";DBG<0,tuple<Ts...>,Ts...>(os,t);os<<")";return os;}
template<class T,class K>ostream&operator<<(ostream&os,pair<T,K>p){DBG(os,p,", ");return os;}
template<class T>ostream&operator<<(ostream&os,vector<T>v){DBG_B(forr(t,v){os<<DBG_DLM(i)<<t;});}
template<class T>ostream&operator<<(ostream&os,set<T>s){DBG_B(forr(t,s){os<<DBG_DLM(i)<<t;});}
template<class T>ostream&operator<<(ostream&os,queue<T>q){DBG_B(for(;q.size();q.pop()){os<<DBG_DLM(i)<<q.front();});}
template<class T>ostream&operator<<(ostream&os,priority_queue<T>q){DBG_B(for(;q.size();q.pop()){os<<DBG_DLM(i)<<q.top();});}
template<class T,class K>ostream&operator<<(ostream&os,map<T,K>m){DBG_B(forr(p,m){os<<DBG_DLM(i);DBG(os,p,"->");});}
template<class T,class K>ostream&operator<<(ostream&os,unordered_map<T,K>m){DBG_B(forr(p,m){os<<DBG_DLM(i);DBG(os,p,"->");});}
#define DBG_OVERLOAD(_1,_2,_3,_4,_5,_6,macro_name,...)macro_name
#define DBG_LINE(){char s[99];sprintf(s,"line:%3d | ",__LINE__);cerr<<s;}
#define DBG_OUTPUT(v){cerr<<(#v)<<"="<<(v);}
#define DBG1(v,...){DBG_OUTPUT(v);}
#define DBG2(v,...){DBG_OUTPUT(v);cerr<<", ";DBG1(__VA_ARGS__);}
#define DBG3(v,...){DBG_OUTPUT(v);cerr<<", ";DBG2(__VA_ARGS__);}
#define DBG4(v,...){DBG_OUTPUT(v);cerr<<", ";DBG3(__VA_ARGS__);}
#define DBG5(v,...){DBG_OUTPUT(v);cerr<<", ";DBG4(__VA_ARGS__);}
#define DBG6(v,...){DBG_OUTPUT(v);cerr<<", ";DBG5(__VA_ARGS__);}
#define DEBUG0(){DBG_LINE();cerr<<endl;}
#ifdef LOCAL
#define out(...){DBG_LINE();DBG_OVERLOAD(__VA_ARGS__,DBG6,DBG5,DBG4,DBG3,DBG2,DBG1)(__VA_ARGS__);cerr<<endl;}
#else
#define out(...)
#endif

using ll=long long;
using pii=pair<int,int>;using pll=pair<ll,ll>;using pil=pair<int,ll>;using pli=pair<ll,int>;
using vs=vector<string>;using vvs=vector<vs>;using vvvs=vector<vvs>;
using vb=vector<bool>;using vvb=vector<vb>;using vvvb=vector<vvb>;
using vi=vector<int>;using vvi=vector<vi>;using vvvi=vector<vvi>;
using vl=vector<ll>;using vvl=vector<vl>;using vvvl=vector<vvl>;
using vd=vector<double>;using vvd=vector<vd>;using vvvd=vector<vvd>;
using vpii=vector<pii>;using vvpii=vector<vpii>;using vvvpii=vector<vvpii>;
template<class A,class B>bool amax(A&a,const B&b){return b>a?a=b,1:0;}
template<class A,class B>bool amin(A&a,const B&b){return b<a?a=b,1:0;}
ll ri(){ll l;cin>>l;return l;} string rs(){string s;cin>>s;return s;}

template<class V, class Merge> struct SegmentTree {
	const int n;
	const V unit_value;
	vector<V> val;

	SegmentTree(int _n) : n(1 << (32-__builtin_clz(_n-1))), unit_value(Merge::unit()), val(n * 2, unit_value) {}

	V get(int i) const { return val[i + n]; }
	void set(int i, const V &v) { val[i + n] = v; }

	void build() {
		for (int i = n - 1; i > 0; i--) val[i] = Merge::merge(val[i * 2], val[i * 2 + 1]);
	}

	void update(int i, const V &v) {
		i += n;
		val[i] = v;
		while (i > 1) {
			i >>= 1;
			val[i] = Merge::merge(val[i * 2], val[i * 2 + 1]);
		}
	}

	V query(int l, int r) const {
		l = max(0, min(n, l)) + n;
		r = max(0, min(n, r)) + n;
		V ret = unit_value;
		for (; l < r; l >>= 1, r >>= 1) {
			if (l & 1) ret = Merge::merge(ret, val[l++]);
			if (r & 1) ret = Merge::merge(ret, val[--r]);
		}
		return ret;
	}
};
template<class V, class Merge> ostream& operator<<(ostream& os, const SegmentTree<V, Merge>& seg) {
	vector<V> vec;
	for (int i = 0; i < seg.n; i++) {
		vec.emplace_back(seg.get(i));
	}
	os << vec;
	return os;
}

template <class V> struct MergeRangeMaxQ {
	static V merge(const V &l, const V &r) { return l > r ? l : r; }
	static V unit() { return numeric_limits<V>::min(); }
};
template<class V> using SegTreeMax = SegmentTree<V, MergeRangeMaxQ<V>>;

template <class T> struct CumulativeSum2D {
	bool built = false;
	vector<vector<T>> A;

	CumulativeSum2D(int h, int w) : A(h + 1, vector<T>(w + 1)) {}

	void add(int y, int x, T v) {
		A[y + 1][x + 1] += v;
	}

	void add(int t, int b, int l, int r, T v) {
		A[t][l] += v;
		A[b][r] += v;
		A[t][r] -= v;
		A[b][l] -= v;
	}

	void build() {
		for (size_t y = 0; y < A.size(); y++) {
			for(size_t x = 1; x < A[y].size(); x++) {
				A[y][x] += A[y][x - 1];
			}
		}
		for (size_t y = 1; y < A.size(); y++) {
			for(size_t x = 0; x < A[y].size(); x++) {
				A[y][x] += A[y - 1][x];
			}
		}
		built = true;
	}

	T query(int t, int b, int l, int r) {
		assert(built);
		return (A[b][r] - A[b][l] - A[t][r] + A[t][l]);
	}

	T query_hw(int t, int l, int h, int w) {
		return query(t, t+h, l, l+w);
	}
};

ll solve() {
	int n = ri(), m = ri();
	vector<ll> A(n);
	rep(i, 1, n) A[i] = ri() + A[i-1];

	vvi B(n, vi(m));
	rep(i, n) rep(j, m) B[i][j] = ri();

	SegTreeMax<pii> seg(n);
	CumulativeSum2D<ll> csum(n, n);

	rep(j, m) {
		rep(i, n) seg.set(i, {B[i][j], i});
		seg.build();

		function<void(int, int)> rec = [&](int l, int r) {
			if (l == r) return;
			int t, i;
			tie(t, i) = seg.query(l, r);
			csum.add(i, r, l, i+1, t);
			rec(l, i);
			rec(i+1, r);
		};
		rec(0, n);
	}

	csum.build();
	out(csum.A);

	ll ans = 0;
	rep(i, n) rep(j, i, n) {
		ll cand = csum.A[j][i] - (A[j] - A[i]);
		amax(ans, cand);
	}
	return ans;
}

void Main() {
	cout << solve() << endl;
}
signed main() {
	cin.tie(nullptr);
	ios::sync_with_stdio(false);
	Main();
	return 0;
}


Measured memory_bytes: 202112