program sie;
type
fxz1=array[1..200,1..200] of longint;
fxz2=array[1..200,1..200] of boolean;
var
f1,f2:text;
i,j,k,n:longint;
map:fxz1;
ans:fxz2;
begin assign(f1,'sie.in');
      assign(f2,'sie.out');
      reset(f1);rewrite(f2);
      readln(f1,n);
      for i:=1 to n do begin for j:=1 to n do begin ans[i,j]:=true;read(f1,map[i,j]);end;
                             readln(f1);
                          end;
      for i:=1 to n-1 do
      for j:=i+1 to n do
      for k:=1 to n do
      if (map[i,j]=map[i,k]+map[k,j])and(k<>i)and(j<>k)and(i<>j) then ans[i,j]:=false;
      for i:=1 to n-1 do
      for j:=i+1 to n do
      if ans[i,j] then writeln(f2,i,' ',j);
      close(f1);close(f2);
end.