#include <fstream>

using namespace std;

unsigned short int d,c[5000005];
unsigned int n,i; 

int main()
{
	ifstream fin("pascal.in");
    ofstream fout("pascal.out");
	
	fin>>n;
	fin>>d;
	
	for(i=1;i<=5000004 && i*d<=5000004;i++)
	{
		if(i%d==0)
		{
			if(c[i]==0)
			{
				c[i]=1;
				c[i*d]=2;
			}
			else
			{
			   c[i*d]=c[i]+1;	
			}
		}
	}
	
	int nr_factori=0,raspuns=0,;
	if(n%2==1)
	{
		for(i=0;i<=(n-1)/2+1;i++)
		{
			nr_factori=nr_factori+c[n-i]-c[i+1];
			if(nr_factori>0)
				raspuns++;
			//numar=numar*(n-i)/(i+1);
			//cout<<numar<<' ';
		}
		fout<<raspuns*2<<'\n';
	}
	else
	{
		for(i=0;i<n/2-1;i++)
		{
			nr_factori=nr_factori+c[n-i]-c[i+1];
			if(nr_factori>0)
				raspuns++;
			//numar=numar*(n-i)/(i+1);
			//cout<<numar<<' ';
		}
		raspuns*=2;
		
		nr_factori=nr_factori+c[n-i]-c[i+1];
			if(nr_factori>0)
				raspuns++;
			//numar=numar*(n-i)/(i+1);
			
			fout<<raspuns<<'\n';
		
	}
	
	fin.close();
	fout.close();
	return 0;
}