CF39B.Company Income Growth

Petya works as a PR manager for a successful Berland company BerSoft. He needs to prepare a presentation on the company income growth since 2001 (the year of its founding) till now. Petya knows that in 2001 the company income amounted to _a_1 billion bourles, in 2002 — to _a_2 billion, ..., and in the current (2000 + n)-th year — a__n billion bourles. On the base of the information Petya decided to show in his presentation the linear progress history which is in his opinion perfect. According to a graph Petya has already made, in the first year BerSoft company income must amount to 1 billion bourles, in the second year — 2 billion bourles etc., each following year the income increases by 1 billion bourles. Unfortunately, the real numbers are different from the perfect ones. Among the numbers a__i can even occur negative ones that are a sign of the company’s losses in some years. That is why Petya wants to ignore some data, in other words, cross some numbers a__i from the sequence and leave only some subsequence that has perfect growth.

Thus Petya has to choose a sequence of years _y_1, _y_2, ..., y__k,so that in the year _y_1 the company income amounted to 1 billion bourles, in the year _y_2 — 2 billion bourles etc., in accordance with the perfect growth dynamics. Help him to choose the longest such sequence.

佩佳在一家成功的贝尔兰公司“贝尔软件”（BerSoft）担任公关经理。他需要准备一份关于该公司自2001年（公司成立之年）至今收入增长情况的演示文稿。佩佳知道：2001年的公司收入为 $a_1$ 十亿布尔币，2002年为 $a_2$ 十亿布尔币，……，而当前（即 $2000 + n$）年第 $n$ 年的收入为 $a_n$ 十亿布尔币。基于这些信息，佩佳决定在演示文稿中展示一条他自认为“完美”的线性增长趋势图。根据佩佳已绘制好的图表，公司在第一年（即2001年）的收入应为 1 十亿布尔币，第二年（即2002年）为 2 十亿布尔币，依此类推——此后每一年收入均比前一年多 1 十亿布尔币。

不幸的是，实际数据与“完美”数值并不一致。在序列 $a_i$ 中甚至可能出现负数，这表示公司在某些年份出现了亏损。因此，佩佳希望忽略部分数据，即从原序列中删去若干项 $a_i$，仅保留一个子序列，使其符合“完美”增长规律。

于是，佩佳需要选出一个年份序列 $y_1, y_2, \dots, y_k$，使得公司在第 $y_1$ 年的收入恰好为 1 十亿布尔币，第 $y_2$ 年为 2 十亿布尔币，……，以此类推，完全符合上述“完美”增长规律。请帮助他选出满足条件的最长序列。

The first line contains an integer n (1 ≤ n ≤ 100). The next line contains n integers a__i ( - 100 ≤ a__i ≤ 100). The number a__i determines the income of BerSoft company in the (2000 + i)-th year. The numbers in the line are separated by spaces.

第一行包含一个整数 $n$（$1 \leq n \leq 100$）。第二行包含 $n$ 个整数 $a_i$（$-100 \leq a_i \leq 100$）。数字 $a_i$ 表示 BerSoft 公司在 $(2000 + i)$ 年的收入。该行中的数字以空格分隔。

Output k — the maximum possible length of a perfect sequence. In the next line output the sequence of years _y_1, _y_2, ..., y__k. Separate the numbers by spaces. If the answer is not unique, output any. If no solution exist, output one number 0.

输出 k —— 完美序列的最大可能长度。
下一行输出年份序列 _y_₁, _y_₂, ..., y__k。数字之间用空格分隔。
若答案不唯一，输出任意一个即可。
若无解，仅输出一个数字 0。