with Text_io; 
procedure PRIMES is 
  package IIO is new Text_IO.Integer_io(integer); --need integer output
 
  N:constant integer:=79; --largest number to be considered

  type PRIME_CLASS is (UNKNOWN, PRIME, COMPOSITE);
 
  type PRIME_CLASSES is array(1..N) of PRIME_CLASS;
 
  STATE: PRIME_CLASSES:=(1..N=>UNKNOWN);  
begin
  iio.Put(1); STATE(1):=PRIME;
  for P in 2..N loop  -- For each possible prime in turn...
 
    if STATE(P)=UNKNOWN then -- it isn't a multiple of a smaller prime
	iio.put(P); STATE(P):=PRIME;
 
	for MULTIPLIER in 2..N loop
		exit when MULTIPLIER * P > N;
		STATE(MULTIPLIER * P):=COMPOSITE;
	end loop;
 
	text_io.new_line;
	for i in 1..N loop
		case STATE(i) is
		when UNKNOWN  => text_io.put("u");
		when PRIME    => text_io.put("P");
		when COMPOSITE=> text_io.put(".");
		end case;
	end loop;
	text_io.skip_line;
    end if;
 
  end loop;
 
end PRIMES;