Problem:
Score : 100 points

Problem Statement

Takahashi has K 500-yen coins. (Yen is the currency of Japan.)
If these coins add up to X yen or more, print Yes; otherwise, print No.

Constraints

1 \leq K \leq 100

1 \leq X \leq 10^5

Input

Input is given from Standard Input in the following format:

K X

Output

If the coins add up to X yen or more, print Yes; otherwise, print No.

Sample Input 1

2 900

Sample Output 1

Yes

Two 500-yen coins add up to 1000 yen, which is not less than X = 900 yen.

Sample Input 2

1 501

Sample Output 2

No

One 500-yen coin is worth 500 yen, which is less than X = 501 yen.

Sample Input 3

4 2000

Sample Output 3

Yes

Four 500-yen coins add up to 2000 yen, which is not less than X = 2000 yen.

Solution in Common Lisp (SBCL 1.1.14) (judge verdict: Accepted)

(defun splitat (c line)
  (labels ((rec (line acc)
				(let ((pos (position-if (lambda(cc) (char= c cc)) line)))
				  (if pos
					  (rec (subseq line (1+ pos)) (cons (subseq line 0 pos) acc))
					(nreverse (cons line acc))))))
	(rec line nil)))
(defun f(k x)
  (<= x (* 500 k)))
(let* ((line (mapcar #'parse-integer (splitat #\space (read-line nil nil)))))
  (format t "~A~%" (if (f (car line) (cadr line)) "Yes" "No")))