program SNT;

uses crt;
var i,n,d:integer;
begin
    clrscr;
    write('Nhap n: ');readln(n);
    d:=0;
    for i:=1 to n do
    if n mod i=0 then d:=d+1;
    if d=2 then write(n,' la SNT')
    else write(n,' khong al SNT');
    readln
end.

program kiem_tra_so_nguyen_to;

uses crt;

var i,n:lonGint;

begin

clrscr;

write('nhap n: ');readln(n);

if (n=0) or (n=1) then 

write(n,' khong la so nguyen to') else 

begin

 i:=1;
    Repeat
       i:= i+1;
    Until (n mod i= 0) or (i*i>n);
    If i*i>n then Writeln (n,' la so nguyen to')
    Else Writeln (n,' khong phai la so nguyen to');
End;
Readln;
End.