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1628.cpp
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1628.cpp
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#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define fr(i,j,k) for(int i=j;i<k;i++)
#define f(n) fr(i,0,n)
#define f1(n) fr(i,1,n+1)
#define pb push_back
#define F first
#define S second
#define all(x) x.begin(), x.end()
const int mod = 1e9 + 7;
const int maxn = 2000005;
int tar;
map<int,int> build(vector<int>v) {
map<int,int>mp;
mp[0] = 1;
for (int i = 1 ; i < (1<<v.size()) ; i++) {
ll sum = 0;
for (int j = 0 ; j < v.size() ; j++) {
if ((1<<j)&i) {
sum += v[j];
}
}
if (sum <= tar) {
mp[sum]++;
}
}
return mp;
}
void solve() {
int n;
cin >> n >> tar;
vector<int>v1,v2;
f(n/2) {
int x;
cin >> x;
v1.pb(x);
}
for (int i = n/2; i < n ; i++) {
int x;
cin >> x;
v2.pb(x);
}
random_shuffle(all(v1));
random_shuffle(all(v2));
auto m1 = build(v1);
auto m2 = build(v2);
ll ans = 0;
for (auto &i : m1) {
if (m2.count(tar - i.F)) {
ans += (ll)i.S * m2[tar-i.F];
}
}
cout << ans << '\n';
}
int main() {
ios_base::sync_with_stdio(0);
cin.tie(0);
int c = 0;
int t;
if (!c) {
t = 1;
}
else {
cin >> t;
}
while (t--) {
solve();
}
}