Program HOC24;

var n: integer;

function nt(x: integer): boolean;

var j: integer;

begin

nt:=true;

if (x=2) or (x=3) then exit;

nt:=false;

if (x=1) or (x mod 2=0) or (x mod 3=0) then exit;

j:=5;

while j<=trunc(sqrt(x)) do

begin

if (x mod j=0) or (x mod (j+2)=0) then exit;

j:=j+6;

end;

nt:=true;

end;

begin

readln(n);

if nt(n) then write(n,' la so nguyen to') else write(n,' khong phai so nguyen to');

readln

end.