#include<fstream.h>
ifstream f("flip.in");
ofstream g("flip.out");
int main()
{
long n,m,i,j,s1,s2,a[16][16];
f>>n>>m;
for (i=1;i<=n;i++)
for (j=1;j<=m;j++)
f>>a[i][j];
for (i=1;i<=n;i++)
{
s1=0;s2=0;
for (j=1;j<=m;j++)
{
s1=s1+a[i][j];
s2=s2+(a[i][j]*(-1));
}
if (s2>s1)
for (j=1;j<=m;j++)
a[i][j]=a[i][j]*(-1);
}
for (j=1;j<=m;j++)
{
s1=0;s2=0;
for (i=1;i<=n;i++)
{
s1=s1+a[i][j];
s2=s2+(a[i][j]*(-1));
}
if (s2>s1)
for (i=1;i<=n;i++)
a[i][j]=a[i][j]*(-1);
}
s1=0;
for (i=1;i<=n;i++)
for (j=1;j<=m;j++)
s1=s1+a[i][j];
g<<s1;
return 0;
}