(import (scheme base) (scheme write))
(define (sum-internal acc i x)
    (define i-plus-one (+ i 1))
    (if (< i x)
        (sum-internal (+ acc i-plus-one) i-plus-one x)
        acc
    )
)
(define (sum x)
    (sum-internal 0 0 x)
)
(display (sum 40))
(newline)
(display (sum 100))
(newline)