program hello;
uses crt;
var i,n: integer
begin
clrscr;
writeln('nhap n'); readln(n);
if n<= 1 then writeln('n ko la snt') else
begin
i:=2;
while n mod i <> 0 do i:=i+1;
if i = n then writeln('n,'la snt')
else writeln('n,'ko phai snt');
end;
readln;
end.