program hio; 
type ma=array [1..16,1..16] of longint; 
ta=array [1..16] of -1..1; 
var n,m,i,j:longint; 
smax:longint; 
a:ma; 
sol:ta; 
f:text; 
procedure evaluare; 
var i,j,s,sc:longint; 
begin
s:=0; 
for i:=1 to m do
begin
sc:=a[1,i]; 
for j:=2 to n do
sc:=sc+sol[j]*a[j,i]; 
s:=s+abs(sc); 
end; 
if smax<s then smax:=s; 
end; 
procedure back(p:integer); 
begin
sol[p]:=1; 
if p=n then evaluare 
else back(p+1); 
sol[p]:=-1; 
if p=n then evaluare 
else back(p+1); 
end; 
begin {pp}
assign(f,'flip.in');reset(f); 
readln(f,n,m); 
for i:=1 to n do
begin
for j:=1 to m do
read (f,a[i,j]); 
readln(f); 
end; 
close(f); 
smax:=0; 
back(1); 
assign(f,'flip.out');rewrite(f); 
write(f,smax); 
close(f); 
end.