#include<iostream>
#include<fstream>
using namespace std;
float a[17][17],l[17],c[17];
unsigned n,m;
void citire()
{
	ifstream f("flip.in");
	f>>n>>m;
	for(unsigned i=1;i<=n;i++)
		{
			for(unsigned int j=1;j<=m;j++)
				{
					f>>a[i][j];
					l[i]=l[i]+a[i][j];
					l[0]=s+l[i];
					c[j]=c[j]+a[i][j];
					c[0]=c+c[0];
				}
		}
	f.close();
	
}

int main()
{
	ofstream g("flip.out");
	citire();
	float sum=0;
	int gata=0;
	while(gata==0)
	{ gata=1;
	for(unsigned i=1;i<=n;i++)
		if(l[i]>0) sum=sum+l[i];
		else
		{
			gata=0;
			sum=sum-l[i];
			for(unsigned int j=1;j<=m;j++)
			{
				c[j]=c[j]+(-1)*(2*a[i][j]);
			}
		}
	for(unsigned i=1;i<=m;i++)
		if(c[i]<0)
		{
			sum=sum+2*c[i]*(-1);
		}	
	}		
	g<<sum;
	g.close();
}