#include <iostream>
using namespace std;
int main()
{
	unsigned long a;
	while(cin>>a)
	{
		unsigned long b,c,sum=10000000000000000000;
		for(b=a+1;b<=a*a+a+1;b++)
		{
			if((a*b+1)%(b-a)==0)
			{
				c=(a*b+1)/(b-a);
				if(sum>(b+c))  sum=b+c;
			}
		}
		cout<<sum<<endl;
	}
	return 0;
}