题目描述
There are $N children, numbered 1, 2, \ldots, N$.
They have decided to share K candies among themselves. Here, for each $i (1 \leq i \leq N), Child i$ must receive between 0 and a_i candies (inclusive). Also, no candies should be left over.
Find the number of ways for them to share candies, modulo 10^9 + 7. Here, two ways are said to be different when there exists a child who receives a different number of candies.
Constraints
- All values in input are integers.
- $1 \leq N \leq 100$
- $0 \leq K \leq 10^5$
- $0 \leq a_i \leq K$
Input
Input is given from Standard Input in the following format:
N K
$a_1 a_2 \ldots a_N$
Output
Print the number of ways for the children to share candies, modulo 10^9 + 7.
Examples
Input
3 4
1 2 3
Output
5
Input
1 10
9
Output
0
Input
2 0
0 0
Output
1
Input
4 100000
100000 100000 100000 100000
Output
665683269
输入格式
见题面
输出格式
见题面