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#9247. 一道简单的计数题

统计

给定三个整数 $k, p, x$。求满足以下条件的整数对 $(a, b)$ 的数量:

  1. $0 \le b \le a < p^k$;
  2. $\binom{a}{b} \equiv x \pmod{p}$。

输入格式

输入仅一行,包含三个整数:$k$ ($1 \le k \le 2^{1000}$),$p$ ($2 \le p \le 5000$) 和 $x$ ($1 \le x < p$)。 整数 $k$ 以二进制形式给出,从最高位开始。 保证 $p$ 是质数,且输入中 $k$ 的第一位数字为 1。

输出格式

输出一个整数,即答案对 $998244353$ 取模的结果。

样例

样例输入 1

1 7 5

样例输出 1

2

样例输入 2

1 43 17

样例输出 2

17

样例输入 3

1111111111 4999 1954

样例输出 3

195378837

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