(define random-list
  (lambda (n)
    (if (zero? n)
        null
        (cons (random 100) (random-list (- n 1))))))

(define nums (random-list 200000))

(define sumr
  (lambda (lst)
    (if (null? lst)
        0
        (+ (car lst) (sumr (cdr lst))))))

(define suml
  (lambda (lst)
    (let kernel ((result 0) (remaining lst))
      (if (null? remaining)
          result
          (kernel (+ result (car remaining)) (cdr remaining))))))

(define repeat
  (lambda (exp times)
    (if (< 0 times)
        (begin
          (eval exp)
          (repeat exp (- times 1))))))