#include<stdio.h>
int a[20][20];
bool v[40];
int main()
{
	freopen("flip.in","r",stdin);
	freopen("flip.out","w",stdout);
	int n,m,i,j;
	long s,max;
	bool t;
	max=0;
	scanf("%d%d",&n,&m);
	for(i=1;i<=n;i++)
		for(j=1;j<=m;j++)
			scanf("%d",&a[i][j]);
		do
		{
			t=1;
			s=0;
		for(i=n+m;i>=1;i--)
			if(v[i]==0)
			{
				v[i]=1;
				break;
			}
			for(j=i+1;j<=n+m;j++)
				v[j]=0;
			for(i=1;i<=n;i++)
				for(j=1;j<=m;j++)
					if(v[i]==v[n+j])
						s=s+a[i][j];
					else
						s=s+-1*a[i][j];
			for(i=1;i<=n+m;i++)
				if(v[i]==0)
					t=0;
				if(s>max)
					max=s;
		}while(t==0);
		printf("%ld",max);
		return 0;
}