题目描述
Problem Statement
Takahashi's shop sells N products. The usual price of the i-th product is A_i yen (Japanese currency).
It has a bargain sale today, with a discount of 1 yen off the usual prices for the 2-nd, 4-th, and the subsequent even-indexed products. The 1-st, 3-rd, and the subsequent odd-indexed products are sold for their usual prices.
You have X yen. Can you buy all the N products with this money?
Input
Input is given from Standard Input in the following format:
N X
$A_1 A_2 \ldots A_N$
Output
If you can buy all the N products, print Yes; otherwise, print No.
Constraints
- $1 \leq N \leq 100$
- $1 \leq X \leq 10000$
- $1 \leq A_i \leq 100$
- All values in input are integers.
Sample Input 1
2 3
1 3
Sample Output 1
Yes
You can buy the 1-st product for 1 yen and the 2-nd product for 2 yen, 1 yen off the usual price. You have just enough money, 3 yen, to buy both of them.
Sample Input 2
4 10
3 3 4 4
Sample Output 2
No
You can buy these four products for 3 yen, 2 yen, 4 yen, and 3 yen, respectively. You need 12 yen to buy all of them, and since you have only 10 yen, you cannot buy all of them.
Sample Input 3
8 30
3 1 4 1 5 9 2 6
Sample Output 3
Yes
输入格式
见题面 Input 部分
输出格式
见题面 Output 部分