using System;
public class Program
{
public static void Main()
int N=5;
int a=2;
int x;
if (N<2)
Console.WriteLine($"{N} khong phai la so nguyen to");
}
else if (N==2)
Console.WriteLine($"{N} la so nguyen to");
else
while (a < N)
x=N%a;
a++;
if (x!=0)
Console.WriteLine($"{x} la so nguyen to");