# include <fstream.h>
void main()
{unsigned long n,k,j,poz=0; int d,v[10]; for(k=1;k<=7;k++) v[k]=0;
cin>>n>>d;
for(k=1;k<=n/2+1;k++)
 { for (j=2;j<=6;j++)
 if(((n-k+1)/k)%j==0) {v[j]=1; }
    if(v[d]==1) poz=k;k=n/2+2;}
  if(poz!=0) cout<<(n+1)-2*poz;else cout<<0;
}