#include <cstdio>
#include <algorithm>
#include <deque>
using namespace std;
int a[301][301];
int sum[301][301];
int dp[301][301];
int r,c;
int mem[301][301];
void prep(){
scanf("%d %d",&r,&c);
for (int i=1; i<=r; i++) {
for (int j=1; j<=c; j++) {
scanf("%d",&a[i][j]);
}
}
for (int i=1; i<=r; i++) {
for (int j=1; j<=c; j++) {
sum[i][j] = sum[i-1][j] + sum[i][j-1] - sum[i-1][j-1] + a[i][j];
}
}
}
int main(){
prep();
for (int j=1; j<=c; j++) {
for (int i=1; i<=r; i++) {
if(j != 1)for (int k=1; k<i; k++) {
dp[i][j] = max(dp[i][j], mem[k][i] - sum[k][j]);
}
dp[i][j] += 2*sum[i][j];
}
for (int i=1; i<=r; i++) {
for (int k=i+1; k<=r; k++) {
if(j == 1) mem[i][k] = dp[i][j] - sum[k][j];
mem[i][k] = max(mem[i][k],dp[i][j] - sum[k][j]);
}
}
}
printf("%d",dp[r][c]-sum[r][c]);
}
