Counting Combinations

Background

Special for beginners, ^_^

Problem Description

There are $n$ positive integers. Find the number of possible ways to choose some of them whose sum is $t$ (where $t$ is also a positive integer). For example:

$n=5$, the $5$ numbers are $1, 2, 3, 4, 5$, and $t=5$.

Then the possible combinations are $5=1+4$, $5=2+3$, and $5=5$, three combinations.

Input Format

The first line contains two positive integers $n$ and $t$, separated by a space, where $1 \le n \le 20$ is the number of positive integers and $t$ is the required sum ($1 \le t \le 1000$).

The next line contains $n$ positive integers separated by spaces.

Output Format

The number of different combinations whose sum is $t$.

Sample Input 1

5 5
1 2 3 4 5

Sample Output 1

3

Constraints

1s, 1024KiB for each test case.