program flip;
var f:text;
        a:array[1..16,1..16] of longint;
        i,j,m,n:byte;
        sum1,sum2:longint;
begin
assign(f,'flip.in');
reset(f);
readln(f,m,n);
for i:=1 to m do
        begin
        for j:=1 to n do
                read(f,a[i,j]);
        readln(f);
        end;
close(f);
for i:=1 to m do
        begin
        sum1:=0;
        sum2:=0;
        for j:=1 to n do begin
                sum1:=sum1+a[i,j];
                sum2:=sum2+a[i,j]*(-1);
                end;
        if sum2>sum1 then for j:=1 to n do a[i,j]:=a[i,j]*(-1);
        end;
for j:=1 to n do
        begin
        sum1:=0;
        sum2:=0;
        for i:=1 to m do begin
                sum1:=sum1+a[i,j];
                sum2:=sum2+a[i,j]*(-1);
                end;
        if sum2>sum1 then for i:=1 to m do a[i,j]:=a[i,j]*(-1);
        end;
sum1:=0;
for i:=1 to m do
        for j:=1 to n do sum1:=sum1+a[i,j];
assign(f,'flip.out');
rewrite(f);
writeln(f,sum1);
close(f);
end.