program ex;
type
 ss=array[1..200,1..200]of integer;
 sz=array[1..200,1..200]of boolean;
var
 map:ss;
 g:sz;
 n:integer;
 i,j,k:integer;
 flag:integer;
begin
 assign(input,'sie.in');
 assign(output,'sie.out');
 reset(input);
 rewrite(output);
 readln(n);
 for i:=1 to n do
  for j:=1 to n do
   read(map[i,j]);
 close(input);
 for i:=1 to n-1 do
  for j:=i+1 to n do
   begin
    flag:=0;
    for k:=1 to n do
     if flag<1 then
     if (i<>k)and(i<>j)and(j<>k) then
      if map[i,j]=map[i,k]+map[k,j] then inc(flag);
    if flag<>0 then
     begin
      g[i,j]:=true;
      g[j,i]:=true;
     end;
   end;
 for i:=1 to n-1 do
  for j:=i+1 to n do
   if not g[i,j] then
    writeln(i,' ',j);
 close(output);
end.