Tanya and Stairways

题目描述： 给你N个数（1≤N≤1000），这N个数是由M个从1开始的连续自然序列组成的 输入输出格式： 输入格式： 第一行，一个数：N 第二行N个数，分别是组成M个序列的元素 输出格式： 第一行，一个数：M 第二行，M个数，分别是这M个序列的长度

Little girl Tanya climbs the stairs inside a multi-storey building. Every time Tanya climbs a stairway, she starts counting steps from $ 1 $ to the number of steps in this stairway. She speaks every number aloud. For example, if she climbs two stairways, the first of which contains $ 3 $ steps, and the second contains $ 4 $ steps, she will pronounce the numbers $ 1, 2, 3, 1, 2, 3, 4 $ . You are given all the numbers pronounced by Tanya. How many stairways did she climb? Also, output the number of steps in each stairway. The given sequence will be a valid sequence that Tanya could have pronounced when climbing one or more stairways.

The first line contains $ n $ ( $ 1 \le n \le 1000 $ ) — the total number of numbers pronounced by Tanya. The second line contains integers $ a_1, a_2, \dots, a_n $ ( $ 1 \le a_i \le 1000 $ ) — all the numbers Tanya pronounced while climbing the stairs, in order from the first to the last pronounced number. Passing a stairway with $ x $ steps, she will pronounce the numbers $ 1, 2, \dots, x $ in that order. The given sequence will be a valid sequence that Tanya could have pronounced when climbing one or more stairways.

In the first line, output $ t $ — the number of stairways that Tanya climbed. In the second line, output $ t $ numbers — the number of steps in each stairway she climbed. Write the numbers in the correct order of passage of the stairways.

7
1 2 3 1 2 3 4

2
3 4 

4
1 1 1 1

4
1 1 1 1 

5
1 2 3 4 5

1
5 

5
1 2 1 2 1

3
2 2 1