Type tablou=array[1..16,1..16]of longint;
var i,j,s:longint;f1,f2:text;n,m:shortint;t:tablou;
Function slin(x:shortint;v:tablou):longint;
var a:shortint;b:longint;
begin
b:=0;
For a:=1 to n do b:=b+v[x,a];
slin:=b;
end;
Function scol(x:shortint;v:tablou):longint;
var a:shortint;b:longint;
begin
b:=0;
For a:=1 to m do b:=b+v[a,x];
scol:=b;
end;
Procedure invlin(x:integer;v:tablou);
var w:integer;
begin
For w:=1 to n do v[x,w]:=-v[x,w];
end;
Procedure invcol(x:integer;v:tablou);
var w:integer;
begin
For w:=1 to n do v[w,x]:=-v[w,x];
end;begin
assign(f1,'flip.in');reset(f1);
assign(f2,'flip.out');rewrite(f2);
read(f1,n);
read(f1,m);
For i:=1 to n do If -slin(i,t)>slin(i,t) then invlin(i,t);
For i:=1 to m do If -scol(i,t)>scol(i,t) then invcol(i,t);
s:=0;
For i:=1 to n do begin
For j:=1 to m do begin
s:=s+t[i,j];
end;
end;
write(f2,s);
close(f1);
close(f2);
end.