#include<bits/stdc++.h>
using namespace std;
int n,m,i,j;
long long a[17][17],sumc[17][17],sumr[17][17],x,ans;
int main()
{
	ios_base::sync_with_stdio(false);cin.tie(0);cerr.tie(0);cout.tie(0);
	freopen("sol.in","r",stdin);
	freopen("sol.out","write",stdout);
	cin>>n>>m;
	for(i=1;i<=n;i++)
	 for(j=1;j<=m;j++)
	  cin>>x,a[i][j]=x,sumr[i][j]=sumr[i][j-1]+x,sumc[i][j]=sumc[i-1][j]+x;
	for(i=1;i<=m;i++)
	 if(sumc[n][i]<0)
	  {
		sumc[n][i]*=(-1);
		for(j=1;j<=n;j++)sumr[j][m]-=2*a[j][i];
	  }
	for(i=1;i<=n;i++)
	{
	  if(sumr[i][m]<0)
	  {
		sumr[i][m]*=(-1);
		for(j=1;j<=m;j++)sumc[j][n]-=2*a[i][j];
	  }
	  ans+=sumr[i][m];
	}
	cout<<ans<<endl;
	return 0;
}