Const
  Sonants:Set of Char=['б','в','г','д','ж','з','л','м','н','р'];
  Letters:Set of Char=['а'..'я']+[',']+[' '];

Var
 S:String;
 C:Char;
 i,k,N,L:integer;
 Found:Set of char;
 p,b1,b2,b3,b4:boolean;

begin    
 p:=false;
 while p=false do
  begin
   Writeln('Введите строку:');
   Readln(S);
   L:=Length(S);
   b1:=false;
   if L<2 then b1:=true;
   if not b1 then
    begin
     b2:=false;
     for i:=1 to L do
      if not (S[i] in Letters) then b2:=true;
    end;
   if not b1 and not b2 then
    begin
     b3:=true;
     for i:=1 to L-1 do
      if S[i]=',' then b3:=false;
    end;
   if not b1 and not b2 and not b3 then
    begin
     b4:=false;
     for i:=2 to L do
      if (S[i]=' ') and not (S[i-1]=',') then b4:=true;
    end;
   if b1 or b2 or b3 or b4 then
     Writeln('Некорректный ввод!')
   else p:=true;
  end;
 Writeln;
 Found:=[];
 N:=1;
 i:=1;
 while (i<L-1) do
  begin
   If (S[i] in Sonants) and not (S[i] in Found) then
    begin
     C:=S[i];
     k:=i;
     while (S[k]<>',') and (k<L) do k:=k+1;
     if S[k]=',' then
      while (S[k]<>C) and (k<L) do k:=k+1;
     if S[k]=C then
      begin
       Found:=Found+[C];
       N:=N+1;
      end;
    end;
   i:=i+1;
  end;

 If N=0 then
  Writeln('Таких букв нет!')
 else
  begin
   Writeln('Результат:');
   for C:='б' to 'р' do
    if C in Found then write(C+' ');
  end;
 Readln
End.