#include <bits/stdc++.h>
using namespace std;

const long long INF = (long long)1e17;

int a[17][17];

int main() {
	freopen("flip.in", "r", stdin);
	freopen("flip.out", "w", stdout);
	int n, m;
	scanf("%d %d", &n, &m);
	for(int i=1;i<=n;i++) 
		for(int j=1;j<=m;j++)
			scanf("%d", &a[i][j]);

	long long mx = -INF;

	for(int i=0;i<(1<<n);i++) {
		for(int j=0;j<(1<<m);j++) {
			long long cur = 0;
			for(int ln=1;ln<=n;ln++) {
				for(int cl=1;cl<=m;cl++) {
					bool invert=false;
					if(i&(1<<(ln-1)))
						invert = !invert;
					if(j&(1<<(cl-1)))
						invert = !invert;
					if(invert)
						cur -= a[ln][cl];
					else
						cur += a[ln][cl];
				}
			}
			if(cur>mx)
				mx = cur;
		}
	}
	printf("%lld", mx);
	return 0;
}