Program AB;

var f,g:text;
    a:array[1..100,1..100] of integer;
    n,m,i,j,sum1,sum2,total:integer;

begin
assign(f,'Flip.in');reset(f);
assign(g,'Flip.out');rewrite(g);
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;

for i:=1 to n do
    begin
        for j:=1 to m do
        begin
        sum1:=sum1+a[i,j];
        a[i,j]:=a[i,j]*(-1);
        sum2:=sum2+a[i,j];
        end;

        if sum1>sum2 then
           for j:=1 to m do a[i,j]:=a[i,j]*(-1);

        sum1:=0;
        sum2:=0;
    end;

for j:=1 to n do
    begin
        for i:=1 to m do
        begin
        sum1:=sum1+a[i,j];
        a[i,j]:=a[i,j]*(-1);
        sum2:=sum2+a[i,j];
        end;

        if sum1>sum2 then
           for i:=1 to m do a[i,j]:=a[i,j]*(-1);

        sum1:=0;
        sum2:=0;
    end;

for i:=1 to n do
        begin
        for j:=1 to m do total:=total+a[i,j];
        end;

writeln(g,total);

close(f);
close(g);
end.