#include<stdio.h>

long a[17][17],l[17],c[17],i,j,n,m,minus;
long sum;


void linie(int k)
{for(i=1; i<=m; i++){a[k][i]*=-1;c[i]+=2*a[k][i];} l[k]*=-1;
sum+=2*l[k];
}
void coloana(int k)
{
for(i=1; i<=n; i++){a[i][k]*=-1;l[i]+=2*a[i][k];}  c[k]*=-1;
sum+=2*c[k];
}

int main(void){
freopen("flip.in","r",stdin);
freopen("flip.out","w",stdout);
scanf("%ld %ld",&n,&m);
for(i=1; i<n+1; i++)for(j=1; j<m+1; j++)
{ scanf("%ld ",&a[i][j]); l[i]+=a[i][j]; c[j]+=a[i][j]; sum+=a[i][j]; }
for(i=1; i<=n; i++)if(l[i]<0)minus++;
for(i=1; i<=m; i++)if(c[i]<0)minus++;

while(minus)
{minus=0;
for(i=1; i<=n; i++)if(l[i]<0)linie(i);
for(i=1; i<=m; i++)if(c[i]<0)coloana(i);
for(i=1; i<=n; i++)if(l[i]<0)minus++;
for(i=1; i<=m; i++)if(c[i]<0)minus++;
}
printf("%ld",sum);


return 0;

}