// C#  program to find smallest number

// evenly divisible by

// all numbers 1 to n

using System;

public class GFG{

    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;

}

// Driver program to test the above function

    static public void Main (){

        long n = 20;

        Console.WriteLine(lcm(n));

    }

//This code is contributed by akt_mit   

}