using namespace std;
#include <bits/stdc++.h>
ifstream fin("flip.in");
ofstream fout("flip.out");
int m, n, max1=0;
int l[16];
int t[16][16];
vector<bool> v(17,0);
int main(){
    int i,j,k,s,s1;
    bool f=false;
    cin >> m >> n;
    for(i=0;i<n;i++) for(j=0;j<m;j++){
		cin >> t[i][j];
		l[i]+=t[i][j];
	}
    while(!f){
        s=0;
        for(j=0;j<m;j++){
			s1=0;
            for(i=0; i<n; i++) if(v[i]==1) s1-=t[i][j];
            else s1+=t[i][j];
            if(s1<0) s1=-s1;
            s+=s1;
        }
        if(s>max1) max1=s;
        for(i=n-1;i>=0 && v[i]==1;i--) v[i]=0;
        if(i>=0)v[i]=1;
        else f=true;
    }
    cout << max1;
    return 0;
}