#include<fstream>
using namespace std;
int main()
{int nr=0,i,j,n,ok,k,c;
 ifstream fin("fractii.in");
 ofstream fout("fractii.out");
 fin>>n;
 nr=n+n-1;
 for(i=2;i<=n;i++)
    for(j=2;j<=n;j++)
      if(i>j){c=2;
	      do{ok=0;
		 for(k=c;k<=j;k++)
		   if(j%k==0) {ok=1;break;}
		 if(ok==1)
		   {ok=0;
		   if(i%k==0) ok=1;
		   }
		   else {ok=0;
			 if(i%k-1==0)ok=1;
			 }
		 c++;
		 }while(ok==0&&c<=j);
	     if(ok==0) nr++;
	     }
    else if(j>i){c=2;
		do{
		  ok=0;
		  for(k=c;k<=i;k++)
		   if(i%k==0) {ok=1;break;}
		  if(ok==1)
		    {ok=0;
		    if(j%k==0) ok=1;
		    }
		    else {ok=0;
			  if(j%(k-1)==0) ok=1;
			  }

		  c++;
		  }while(ok==0&&c<=i);
	       if(ok==0) nr++;
	       }


 fout<<nr;
 fin.close();
 fout.close();
 return 0;
 }