Odds and Ends

题意翻译

给你一个数列a${_1}$,a${_2}$,……,a${_n}$ 现在要求你把这个数列分成奇数个子数列，每个子数列都有奇数个数字，且每个数列的第一个与最后一个必须是奇数 问你能不能做到，能做到输出Yes，不能则输出No

题目描述

Where do odds begin, and where do they end? Where does hope emerge, and will they ever break? Given an integer sequence $ a_{1},a_{2},...,a_{n} $ of length $ n $ . Decide whether it is possible to divide it into an odd number of non-empty subsegments, the each of which has an odd length and begins and ends with odd numbers. A subsegment is a contiguous slice of the whole sequence. For example, $ {3,4,5} $ and $ {1} $ are subsegments of sequence $ {1,2,3,4,5,6} $ , while $ {1,2,4} $ and $ {7} $ are not.

输入输出格式

输入格式

The first line of input contains a non-negative integer $ n $ ( $ 1<=n<=100 $ ) — the length of the sequence. The second line contains $ n $ space-separated non-negative integers $ a_{1},a_{2},...,a_{n} $ ( $ 0<=a_{i}<=100 $ ) — the elements of the sequence.

输出格式

Output "Yes" if it's possible to fulfill the requirements, and "No" otherwise. You can output each letter in any case (upper or lower).

输入输出样例

输入样例 #1

3
1 3 5

输出样例 #1

Yes

输入样例 #2

5
1 0 1 5 1

输出样例 #2

Yes

输入样例 #3

3
4 3 1

输出样例 #3

No

输入样例 #4

4
3 9 9 3

输出样例 #4

No

说明

In the first example, divide the sequence into $ 1 $ subsegment: $ {1,3,5} $ and the requirements will be met. In the second example, divide the sequence into $ 3 $ subsegments: $ {1,0,1} $ , $ {5} $ , $ {1} $ . In the third example, one of the subsegments must start with $ 4 $ which is an even number, thus the requirements cannot be met. In the fourth example, the sequence can be divided into $ 2 $ subsegments: $ {3,9,9} $ , $ {3} $ , but this is not a valid solution because $ 2 $ is an even number.