Program perechi_cuv;
var f,g:text;
    n,i,j,x,p:integer;
    cuvinte:array[1..100] of string;
Begin
assign(f,'date.in');assign(g,'date.out');
reset(f);rewrite(g);
read(f,n);x:=0;
for i:=1 to n do readln(f,cuvinte[i]);
for i:=1 to n do begin
 for j:=1 to n do begin
  if not(i=j) then
   p:=pos(cuvinte[i],cuvinte[j]);
  if p<>0 then begin
   writeLN(g,cuvinte[i],' ',cuvinte[j]);
   x:=x+1;end;end;
 end;
if x=0 then write(g,'Nu exista solutii');
close(f);close(g);
end.