using System;

​

​

public class Program

{

    public static void Main()

    {

        Console.WriteLine("Hello World");

          long n = 20;  

        Console.WriteLine(lcm(n));  

    }

    static long gcd(long a, long b)  

    {  

        if(a%b != 0)  

            return gcd(b,a%b);  

        else

            return b;  

    }  

// Function returns the lcm of first n numbers  

    static long lcm(long n)  

    {  

        long ans = 1;      

        for (long i = 1; i <= n; i++)  

            ans = (ans * i)/(gcd(ans, i));  

        return ans;  

    }  

}