Problem Statement

Hop Sugoroku There is a row of $N$ squares labeled $1, 2, \dots, N$ and a sequence $A = (A_1, A_2, \dots, A_N)$ of length $N$. Initially, square $1$ is painted black, the other $N - 1$ squares are painted white, and a piece is placed on square $1$. You may repeat the following operation any number of times, possibly zero: When the piece is on square $i$, choose a positive integer $x$ and move the piece to square $i + A_i \times x$. Here, you cannot make a move with $i + A_i \times x > N$. Then, paint the square $i + A_i \times x$ black. Find the number of possible sets of squares that can be painted black at the end of the operations, modulo $998244353$. Constraints All input values are integers. $1 \le N \le 2 \times 10^5$ $1 \le A_i \le 2 \times 10^5$ Input Format: The input is given from Standard Input in the following format: N A_1 A_2 ... A_N Output Format: Print the answer as an integer. Examples: Example 1: Input: 5 1 2 3 1 1 Output: 8