(use srfi.13)

(define yuki279
  (let*
    (
      (s (read-line))
      (t (string-count s #\t))
      (r (string-count s #\r))
      (e (string-count s #\e))
      (ans (min t r (quotient e 2)) )
    )
    (write ans)
    (newline)
  )
)