8VC Venture Cup 2017 - Final Round
E
Byteland coins
Codeforces
3200
原题
← DF →
翻译中…

There are $*n*$ types of coins in Byteland. Conveniently, the denomination of the coin type $*k*$ divides the denomination of the coin type $*k* + 1$, the denomination of the coin type $1$ equals $1$ tugrick. The ratio of the denominations of coin types $*k* + 1$ and $*k*$ equals $*a*_{*k*}$. It is known that for each $*x*$ there are at most 20 coin types of denomination $*x*$.

翻译中…

Byteasar has $*b*_{*k*}$ coins of type $*k*$ with him, and he needs to pay exactly $*m*$ tugricks. It is known that Byteasar never has more than $3·10^{5}$ coins with him. Byteasar want to know how many ways there are to pay exactly $*m*$ tugricks. Two ways are different if there is an integer $*k*$ such that the amount of coins of type $*k*$ differs in these two ways. As all Byteland citizens, Byteasar wants to know the number of ways modulo $10^{9} + 7$.

翻译中…

Input

翻译中…

The first line contains single integer $*n*$ ($1 ≤ *n* ≤ 3·10^{5}$) — the number of coin types.

翻译中…

The second line contains $*n* - 1$ integers $*a*_{1}$, $*a*_{2}$, $...$, $*a*_{*n* - 1}$ ($1 ≤ *a*_{*k*} ≤ 10^{9}$) — the ratios between the coin types denominations. It is guaranteed that for each $*x*$ there are at most 20 coin types of denomination $*x*$.

翻译中…

The third line contains $*n*$ non-negative integers $*b*_{1}$, $*b*_{2}$, $...$, $*b*_{*n*}$ — the number of coins of each type Byteasar has. It is guaranteed that the sum of these integers doesn't exceed $3·10^{5}$.

翻译中…

The fourth line contains single integer $*m*$ ($0 ≤ *m* < 10^{10000}$) — the amount in tugricks Byteasar needs to pay.

翻译中…

Output

翻译中…

Print single integer — the number of ways to pay exactly $*m*$ tugricks modulo $10^{9} + 7$.

翻译中…

Note

翻译中…

In the first example Byteasar has $4$ coins of denomination $1$, and he has to pay $2$ tugricks. There is only one way.

翻译中…

In the second example Byteasar has $4$ coins of each of two different types of denomination $1$, he has to pay $2$ tugricks. There are $3$ ways: pay one coin of the first type and one coin of the other, pay two coins of the first type, and pay two coins of the second type.

翻译中…

In the third example the denominations are equal to $1$, $3$, $9$.

翻译中…

样例

Input #1
1

4
2
Output #1
1
InputCopy OutputCopy
Input #2
2
1
4 4
2
Output #2
3
InputCopy OutputCopy
Input #3
3
3 3
10 10 10
17
Output #3
6
InputCopy OutputCopy
题目信息
题号
756E
时间限制
1 s
内存限制
512 MB
标签
组合数学
动态规划
数学

题面与样例版权归 Codeforces 及出题人所有;中文翻译由 AI 生成(CI 管线),如有出入请以原文为准。