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 PHP7 (7.0.15) (judge verdict: Runtime Error)

<?php
fscanf(STDIN, "%d%d", $n, $m);
$a = array_map("intval", explode(" ", trim(fgets(STDIN))));
foreach($a as $i => $dummy)$a[$i] /= 2;
$lcm = lcmAll($a);
if($lcm > $m){
    echo 0;
}else{
    echo intdiv(intdiv($m, $lcm) + 1, 2);
}

//最大公約数
function gcd($m, $n){
    if(!$n)return $m;
    return gcd($n, $m % $n);
}
//配列の最小公倍数
function lcmAll($array){
    $lcm = $array[0];
    for($i = 1; $i < count($array); $i++){
        $lcm = lcm($lcm, $array[$i]);
    }
    $lcm = min($lcm, 10**10);
    return $lcm;
}
//最小公倍数
function lcm($a, $b) {
    return $a / gcd($a, $b) * $b;
}