character(len=1000000)::str
  integer::num(ICHAR('a'):ICHAR('z'))
  integer::t,r,e,i
  data t,r,e/0,0,0/
  data num/26*0/
  read *, str
  do i=1,LEN_TRIM(str)
     num(ICHAR(str(i:i))) = num(ICHAR(str(i:i))) + 1
  end do
  t = num(ICHAR('t'))
  r = num(ICHAR('r'))
  e = num(ICHAR('e'))
  print '(i0)', MINVAL((/t,r,e/2/))

end program