program poduri;
var pod:array[1..100,1..3] of integer;
    np,i,ni,j,l,t,tmp:integer;
    ins,x:array[1..50] of integer;
    vb1,vb2,vb:boolean;
procedure back(k:integer);
begin
  if k>np then
          begin
            for i:=1 to np do write(x[i],'-');
            writeln;
            readln
          end
         else
          begin
           for i:=1 to np do
             begin
               vb:=true;
               for j:=1 to k-1 do
                  if x[j]=i then vb:=false;
               if vb then
                 if k=1 then  begin
                                x[k]:=i;
                                back(k+1);
                              end
                      else if (pod[x[k-1],3]=pod[i,2]) or (pod[x[k-1],3]=pod[i,3]) then
                              begin
                              if pod[x[k-1],3]=pod[i,3] then
                                begin
                                  tmp:=pod[i,3];
                                  pod[i,3]:=pod[i,2];
                                  pod[i,2]:=tmp
                                end;
                                x[k]:=i;
                                back(k+1);
                              end;
             end

          end;
end;
begin
  write(' numarul de poduri: ');readln(np);
  ni:=0;
  for i:=1 to np do
    begin
     write(' pod de la insula :');readln(pod[i,2]);
     write('la insula:');readln(pod[i,3]);
     pod[i,1]:=i;
     vb1:=false;
     vb2:=false;
     for l:=1 to ni do
        begin
        if ins[l]=pod[i,2] then vb1:=true;
        if ins[l]=pod[i,3] then vb2:=true;
        end;
        if not vb1 then
                    begin
                     ni:=ni+1;
                     ins[ni]:=pod[i,2];
                    end;
        if not vb2 then
                    begin
                     ni:=ni+1;
                     ins[ni]:=pod[i,3];
                    end;

    end;
writeln('numarul de insule este:',ni);
back(1)
end.