program sie(input,output);
var
 map:array[1..200,1..200]of longint;
 f:array[1..200,1..200]of boolean;
 n,i,j,k: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]);
 fillchar(f,sizeof(f),false);
 for k:=1 to n do
  for i:=1 to n do
   for j:=1 to n do
    if not f[i,j] then begin
     if (map[i,k]<>0)and(map[k,j]<>0)and(map[i,j]<>0) then
      if map[i,k]+map[k,j]=map[i,j] then f[i,j]:=true;
    end;
 for i:=1 to n do
  for j:=i+1 to n do
   if not (f[i,j]) then writeln(i,' ',j);
 close(input);close(output);
end.