var i,n,k,j,s:longint;
    a:array[1..3,1..50000]of longint;
    f,g:text;
begin
 assign(g,'inundatii.in');
 readln(g,n);
 for i:=1 to n do begin
  for j:=1 to 3 do
   read(g,a[j,i]);
  readln(g);
  end;
 close(g);
 s:=0;
 for i:=1 to n-1 do
  for j:=1 to 3 do begin
   k:=a[j,i]-a[j,i+1];
   if k mod 2=1 then k:=(k div 2)+1
    else k:=k div 2;
   s:=s+(k*2);
   a[j,i]:=a[j,i]-k;
   a[j,i+1]:=a[j,i+1]+k;
   end;
 assign(f,'inundatii.out');
 rewrite(f);
 writeln(f,s);
 close(f);
end.