uses crt;

var N, i, h, j, k : integer; 

function KT (N : integer) : boolean;

begin

    KT := true; i := 2;

    while (i < N) and (KT = true) do

        begin

            if N mod i = 0 then KT := false;

            i := i + 1;

        end;

    if N < 2 then KT := false;

end;

procedure KNT;

begin

    i := 2; 

    while i <= N do

        begin

            h := 1;

            if k = 0 then k := 1;

            for j := 2 to i do 

                if i mod j = 0 then h := 0;

            if (h = 0) and (N mod i = 0) then 

                begin 

                    if k = 1 then 

                        begin 

                            write(i);

                            k := 2; 

                        end 

                    else write('.', i);

                    N := N div i;

               end 

              else i := i + 1;

    end;

end;

begin

clrscr;

write('Nhap N = '); readln(N);

if KT(N) then write(N, ' la so nguyen to')

else

    begin

        write(N,' = ');

        KNT;

    end;

readln

end.