program p1;
uses crt;
var t:array[1..16,1..16] of real;
    i,j,m,n,q:longint;
    sum,sum1:real;
    f,g:text;
begin
assign(f,'flip.in');
reset(f);
readln(f,m,n);
for i:=1 to m do
 for j:=1 to n do
 readln(f,t[i,j]);
assign(g,'flip.out');
rewrite(g);

        for i:=1 to m do
        begin
        sum:=0;
        sum1:=0;
        for j:=1 to n do
        sum:=sum+t[i,j];
        if j=n then for q:=1 to n do
            sum1:=sum1+t[i,q]*(-1);

            if sum1>sum then for q:=1 to n do t[i,q]:=t[i,q]*(-1);
            end;
for i:=1 to n do
begin
sum:=0;
sum1:=0;
for j:=1 to m do
sum:=sum+t[j,i];
if j=m then for q:=1 to m do
            sum1:=sum1+t[q,i]*(-1);
            if sum1>sum then for q:=1 to m do t[q,i]:=t[q,i]*(-1);
            end;

sum:=0;
for i:=1 to m do
for j:=1 to n do
sum:=sum+t[i,j];
writeln(g,sum:5:0);
close(f);
close(g);
end.