#lang racket

(let-values ([(x y)
  (with-input-from-file "../input/02"
    (lambda ()
      (for/fold ([x 0]
                 [y 0])
                ([line (in-lines)])
        (let ([s (string-split line)])
        (let ([op (car s)]
              [num (string->number (car (cdr s)))])
          (match op
            ["up" (values x (- y num))]
            ["down" (values x (+ y num))]
            ["forward" (values (+ x num) y)]))))))
]) (values (cons x y) (* x y)))