var p,s,i,a,n,m:longint;f,g:text;
begin
assign (f,'flip.in');
reset (f);
assign (g,'flip.out');
rewrite (g);
read (f,n,m);
p:=0;
repeat
for i:=1 to m do
s:=0;
begin
read (f,a);
s:=s+a;
end;
p:=p+abs(s);
until eof (f);
write (g,p);
close (g);
end.