#include<iomanip>
#include<limits>
#include<thread>
#include<utility>
#include<iostream>
#include<string>
#include<algorithm>
#include<set>
#include<map>
#include<vector>
#include<stack>
#include<queue>
#include<cmath>
#include<numeric>
#include<cassert>
#include<random>
#include<chrono>
#include<unordered_set>
#include<unordered_map>
#include<fstream>
#include<list>
#include<functional>
#include<bitset>
#include<complex>
#include<tuple>
using namespace std;
typedef unsigned long long int ull;
typedef long long int ll;
typedef pair<ll,ll> pll;
typedef pair<int,int> pi;
typedef pair<double,double> pd;
typedef pair<double,ll> pdl;
#define F first
#define S second
const ll E=1e18+7;
const ll MOD=1000000007;

//0-index
template<typename T,typename U> //T::要素,U::作用素
class late_seg_tree{
private:
    typedef pair<T,U> node;
    vector<vector<node>> tree;
    ll high;
    T err_T;
    U err_U;
    ll err;
    
    T F(T,T); //要素のマージ (要素,要素)
    T G(T,U,ll); //作用素->要素 (要素,作用素,場所)
    U H(U,U); //作用素のマージ (作用素,作用素)
    T I(T,U,ll,ll); //作用素->区間要素 (要素,作用素,l,r) [l,r)
    
    ll bit_size(ll a){
        for(int i=1;i<63;i++){
            if(1<<i >= a){return i;}
        }
        return err;
    }
    
    //[l,r)
    void update(ll h,ll where,ll l,ll r,U u){
        ll L=where<<(high-h-1);
        ll R=(where+1)<<(high-h-1);
        if(r<=L || R<=l){return;}
        if(h==high-1){tree[h][where].F=G(tree[h][where].F,u,where); return;}
        if(l<=L && R<=r){
            tree[h][where].S=H(tree[h][where].S,u);
            tree[h][where].F=F(tree[h+1][where*2].F,tree[h+1][where*2+1].F);
            tree[h][where].F=I(tree[h][where].F,tree[h][where].S,L,R);
        }
        else{
            update(h+1,where*2,l,r,u);
            update(h+1,where*2+1,l,r,u);
            tree[h][where].F=F(tree[h+1][where*2].F,tree[h+1][where*2+1].F);
            tree[h][where].F=I(tree[h][where].F,tree[h][where].S,L,R);
        }
    }
    
    T search(ll h,ll where,ll l,ll r){
        ll L=where<<(high-h-1);
        ll R=(where+1)<<(high-h-1);
        if(r<=L || R<=l){return err_T;}
        if(h==high-1){return tree[h][where].F;}
        if(l<=L && R<=r){return tree[h][where].F;}
        else{
            update(h+1,where*2,L,R,tree[h][where].S);
            update(h+1,where*2+1,L,R,tree[h][where].S);
            tree[h][where].S=err_U;
            T ret=err_T;
            ret=F(ret,search(h+1,where*2,l,r));
            ret=F(ret,search(h+1,where*2+1,l,r));
            return ret;
        }
        return err_T;
    }
    
public:
    late_seg_tree(ull size,T err_T,U err_U):err_T(err_T),err_U(err_U){
        err=1e18+7;
        high=bit_size(size)+1;
        tree.resize(high);
        for(int i=0;i<high;i++){
            tree[i].resize(1<<i,{err_T,err_U});
        }
    }
    
    late_seg_tree(vector<T> t,T err_T,U err_U):err_T(err_T),err_U(err_U){
        err=1e18+7;
        high=bit_size(t.size())+1;
        tree.resize(high);
        for(int i=0;i<high;i++){
            tree[i].resize(1<<i,{err_T,err_U});
        }
        for(int i=0;i<t.size();i++){
            tree[high-1][i]={t[i],err_U};
        }
        for(ll h=high-2;h>=0;h--){
            for(int i=0;i<tree[h].size();i++){
                tree[h][i].F=F(tree[h+1][i*2].F,tree[h+1][i*2+1].F);
            }
        }
    }
    
    void update(ll l,ll r,U u){
        update(0,0,l,r,u);
    }
    
    T search(ll l,ll r){
        return search(0,0,l,r);
    }
};


int main(){
    ll n,m;
    cin>>n>>m;
    vector<ll> A(n,0);
    vector<vector<pll>> B(m,vector<pll>(n));
    for(int i=1;i<n;i++){cin>>A[i];}
    for(int i=1;i<n;i++){A[i]+=A[i-1];}
    for(int i=0;i<n;i++){
        for(int t=0;t<m;t++){
            cin>>B[t][i].F;
            B[t][i].S=i;
        }
    }
    vector<vector<ll>> dp(n+1,vector<ll>(n+1,0));
    for(int i=0;i<m;i++){
        set<ll> S;
        sort(B[i].begin(),B[i].end(),greater<pll>());
        S.insert(-1);
        S.insert(n);
        for(auto &I:B[i]){
            auto it=S.upper_bound(I.S);
            ll r=(*it)-1;
            it--;
            ll l=(*it)+1;
            ll w=I.S;
            dp[l][w]+=I.F;
            dp[l][r+1]-=I.F;
            dp[w+1][w]-=I.F;
            dp[w+1][r+1]+=I.F;
            S.insert(w);
        }
    }
    for(auto &I:dp){
        for(int t=1;t<=n;t++){I[t]+=I[t-1];}
    }
    for(int t=0;t<=n;t++){
        for(int i=1;i<=n;i++){dp[i][t]+=dp[i-1][t];}
    }
    
    ll ans=0;
    for(int i=0;i<n;i++){
        for(int t=i;t<n;t++){ans=max(ans,dp[i][t]-(A[t]-A[i]));}
    }
    cout<<ans<<endl;
    
    
    return 0;
}


Measured memory_bytes: 211712