#include<stdio.h>
using namespace std;
int a[17][17], n, m, N;
int sMax;
int st[40];
int l[17];
int c[17];

void test()
{
    int s=0,j,i,k,sum;
    for(i=1;i<=n;i++)
        {sum=0;
        for(j=1;j<=m;j++)
            if(st[j]==1)
               sum-=a[i][j];
            else
                sum+=a[i][j];
        if(sum<0)
             s=s-sum;
        else
            s=s+sum;
        if(s>sMax)
            sMax=s;
        }

}



void bt(int k)
{  for(int i=0;i<=1;i++)
    {st[k]=i;
    if(k==m)
      test();
    else
        bt(k+1);
    }
}

int main()
{
    FILE *fin,*fout;
    fin=fopen("flip.in","r");
    fout=fopen("flip.out","w");
    fscanf(fin,"%d%d",&m,&n);
    int i, j;
    for(i=1; i<=n; i++)
    {
        for(j=1; j<=m; j++)
        {   fscanf(fin,"%d",&a[i][j]);
            sMax+=a[i][j];
            l[i]+=a[i][j];
        }
    }
    N=n+m;

    int r=1, s, k;
    bt(1);
    fprintf(fout,"%d",sMax);
    return 0;
}