using System;
class Daoanhviet96{
    static void Main(string[] args){
        int n = int.Parse(Console.ReadLine());
        bool kt = true;
        for (int i=2; i<n; i++){
            if (n%i==0) kt=false;
        }
        if (kt) Console.WriteLine("{0} la so nguyen to",n);
        else Console.WriteLine("{0} khong la so nguyen to",n);
    }
}

$\color{green}{\text{Cần code C/C++, Python, Java, JavaScript thì nói để mình thêm}}$

$\color{red}{\text{#Daoanhviet96}}$

uses crt;

var i, N, h : integer;

begin

clrscr;

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

i := 1; h := 1;

for i := 2 to N - 1 do

    if N mod i = 0 then h := 0;

if (h = 1) and (N > 1) then

write(N, ' la so nguyen to')

else write(N, ' khong la so nguyen to');

readln

end.