character(len=1000000)::str
  integer::t,r,e,i
  data t,r,e/0,0,0/
  read *, str
  do i = 1, LEN_TRIM(str)
     select case(str(i:i))
     case('t')
        t = t + 1
     case('r')
        r = r + 1
     case('e')
        e = e + 1
     end select
  end do
  print '(i0)', MINVAL((/t,r,e/2/))

end program