#include<stdio.h>
int v[17][17],n,m;
void citire(int n,int m)
{
	int i=0,p=0;
	for(i=0;i<=n;++i)
	{
		while(p<=m)
		{
			if(p==m)
				break;
			scanf("%d",&v[i][p]);
			++p;
		}
		p=0;
	}
}
int main()
{
	int j=0,k1=0,k2=0,sum1=0,sum2=0,suma=0;
	freopen("flip.in","r",stdin);
	freopen("flip.out","w",stdout);
	scanf("%d%d",&n,&m);
	citire(n,m);
	for(;j<=n;++k1 && ++k2)
	{
		while(j<=n)
		{
			if(j==n)
				break;
			sum1=sum1+v[j][k1];
			++j;
		}
		while(j<=n)
		{
			if(j==n)
				break;
			sum2=sum2+(-v[j][k2]);
			++j;
		}
		if(sum1>sum2)
			suma=suma+sum1;
		else suma=suma+sum2;
		k1=0;
		k2=0;
		sum1=0;
		sum2=0;
	}
	printf("%d",suma);
	return 0;
}