#include<iostream.h>
#include<fstream.h>
//#include<conio.h>
#include<math.h>


int prim(long x)
{ long i;
  int ok=1;
  if (x==2) return 1;
  else
  for (i=3;i<=(long) sqrt(x);i=i+2)
    if (x%i==0)  {ok=0;break;}

  return ok;

}


int cmmdc(long x, long y)
{ int r;
  if (x<y){ r=x;x=y;y=r;}
  if (x%2==0 && y%2==0) return 0;
  if (prim(x) || prim(y)) return 1;
  r=x%y;
  while  (r!=0)
    { x=y;
      y=r;
      r=x%y;
    }
  return y;
}

int  main()


{
 long a[1001];
 long n,s=0;
 long x,y,i,j;
 fstream f("pairs.in",ios::in);
 fstream g("pairs.out",ios::out);
 f>>n;
 for (i=1;i<=n;i++)
   f>>a[i];

 for (i=1;i<=n-1;i++)
   for (j=i+1;j<=n;j++)
     if (cmmdc(a[i],a[j])==1 )
       {cout<<a[i]<<" "<<a[j]<<endl;
	 s++;
       }

cout<<s;
return 0;
}