/* Check cf5-opt.vim defs.
VIM: let g:lcppflags="-std=c++11 -O2 -pthread"
VIM: let g:wcppflags="/O2 /EHsc /DWIN32"
*/
#include <iostream>
#include <exception>

/*
Smallest multiple
Problem 5

2520 is the smallest number that can be divided by each of the numbers from 1 to 10 without any remainder.

What is the smallest positive number that is evenly divisible by all of the numbers from 1 to 20?

Solution:
232792560
*/

long long lacking_factor( long long n, long long m )
{
	long long h = (long long)sqrt(double(n));
	long long l = 1;
	for ( long long i = 2; i <= h; )
		if ( n%i )
			++i;
		else
		{
			n/=i;
			h = (long long)sqrt(double(n));
			if ( m%i )
				l*=i;
			else
				m/=i;
		}
			
	if ( m%n )
		l *= n;
	return l;
}


int main ( void )
{
	long long m = 1;
	for ( int i = 2; i <= 20; ++i )
	{
		m *= lacking_factor( i, m );
		//std::cout << i << " " << m << std::endl;
	}

	std::cout << m << std::endl;

	return 0;
}

