program ABC_053_C_XYetAnotherDieGame
   implicit none
   integer(8) x
   read(*, *) x
   if(mod(x,11) == 0) then
	   write(*, *) 2 * (x / 11)
   else if(mod(x,11) <= 6) then
	   write(*, *) 2 * (x / 11) + 1
   else 
	   write(*, *) 2 * (x / 11) + 2
   end if
end program ABC_053_C_XYetAnotherDieGame