#include<bits/stdc++.h>
using namespace std;
const int MAXN=205;
const int INF=100000000;
int N,M,ans;
int minval,maxval,tmp1,tmp2;
int a[MAXN][MAXN],tmp[MAXN][MAXN];
int p[MAXN][MAXN],q[MAXN][MAXN],dp[MAXN];
void Transpose(){
    for (int i=1;i<=M;i++)
        for (int j=1;j<=N;j++)
            tmp[i][j]=a[j][M-i+1];
    swap(N,M);
    memset(a,0,sizeof(a));
    for (int i=1;i<=N;i++)
        for (int j=1;j<=M;j++)
            a[i][j]=tmp[i][j];
}
void Solve(){
    memset(p,0,sizeof(p));
    memset(q,0,sizeof(q));
    for (int i=1;i<=N;i++){
        memset(dp,0,sizeof(dp));
        maxval=-INF,minval=INF;
        for (int j=i;j<=N;j++){
            tmp1=tmp2=0;
            for (int k=1;k<=M;k++){
                dp[k]+=a[j][k];
                tmp1+=dp[k],tmp1=max(tmp1,0);
                maxval=max(maxval,tmp1);
                tmp2+=dp[k],tmp2=min(tmp2,0);
                minval=min(minval,tmp2);
            }
            p[i][j]=maxval,q[i][j]=minval;
        }
    }
    for (int i=1;i<=N-1;i++)
        for (int j=i;j<=N-1;j++){
            ans=max(ans,p[i][j]*p[j+1][N]);
            ans=max(ans,q[i][j]*q[j+1][N]);
        }
}
int main(){
    scanf("%d%d",&N,&M);
    for (int i=1;i<=N;i++)
        for (int j=1;j<=M;j++)
            scanf("%d",&a[i][j]);
    if (N*M==2){
        if (N==1) printf("%d",a[1][1]*a[1][2]);
        if (M==1) printf("%d",a[1][1]*a[2][1]);
        return 0;
    }
    Solve();
    Transpose();
    Solve();
    printf("%d",ans);
    return 0;
}