#include <bits/stdc++.h>
using namespace std;

const int maxn=31;
int dp[maxn][maxn][maxn][maxn];
bool vis[maxn][maxn][maxn][maxn];
int table[maxn][maxn];

int solve(int a,int b,int c,int d){
    if(a>b||c>d)return 0;
    if(vis[a][b][c][d])return dp[a][b][c][d];
    vis[a][b][c][d]=true;
    int sum=0,best=INT_MIN;
    for(int i=c;i<=d;i++)sum+=table[a][i];
    best=max(best,sum-solve(a+1,b,c,d));
    sum=0;
    for(int i=c;i<=d;i++)sum+=table[b][i];
    best=max(best,sum-solve(a,b-1,c,d));
    sum=0;
    for(int i=a;i<=b;i++)sum+=table[i][c];
    best=max(best,sum-solve(a,b,c+1,d));
    sum=0;
    for(int i=a;i<=b;i++)sum+=table[i][d];
    best=max(best,sum-solve(a,b,c,d-1));
    return dp[a][b][c][d]=best;
}

int main(){
    int n,m;cin>>n>>m;
    int total=0;
    for(int i=0;i<n;i++)for(int j=0;j<m;j++){
        cin>>table[i][j];
        total+=table[i][j];
    }
    int advantage=solve(0,n-1,0,m-1);
    cout<<(total+advantage)/2<<'\n';
}