#include <bits/stdc++.h>
using namespace std;
// macros
typedef long long ll;
typedef long double ld;
typedef pair<int, int> ii;
typedef pair<ll, ll> lll;
typedef tuple<int, int, int> iii;
typedef vector<int> vi;
typedef vector<ii> vii;
typedef vector<iii> viii;
typedef vector<ll> vll;
typedef vector<lll> vlll;
#define REP(a,b,c) for(int a=int(b); a<int(c); a++)
#define RE(a,c) REP(a,0,c)
#define RE1(a,c) REP(a,1,c+1)
#define REI(a,b,c) REP(a,b,c+1)
#define REV(a,b,c) for(int a=int(c-1); a>=int(b); a--)
#define FOR(a,b) for(auto& a : b)
#define all(a) a.begin(), a.end()
#define INF 1e9
#define EPS 1e-9
#define pb push_back
#define popb pop_back
#define fi first
#define se second
#define sz size()
mt19937_64 rng(chrono::steady_clock::now().time_since_epoch().count());
// input
template<class T> void IN(T& x) {cin >> x;}
template<class H, class... T> void IN(H& h, T&... t) {IN(h); IN(t...); }
// output
template<class T1, class T2> void OUT(const pair<T1,T2>& x);
template<class T> void OUT(const T& x) {cout << x;}
template<class H, class... T> void OUT(const H& h, const T&... t) {OUT(h); OUT(t...); }
template<class T1, class T2> void OUT(const pair<T1,T2>& x) {OUT(x.fi,' ',x.se);}
template<class... T> void OUTL(const T&... t) {OUT(t..., "\n"); }
template<class H> void OUTLS(const H& h) {OUTL(h); }
template<class H, class... T> void OUTLS(const H& h, const T&... t) {OUT(h,' '); OUTLS(t...); }
//===================//
// Added libraries //
//===================//
//===================//
//end added libraries//
//===================//
void program();
int main() {
ios_base::sync_with_stdio(false);
cin.tie(NULL);
cout.tie(NULL);
program();
}
//===================//
// begin program //
//===================//
const int MX = 2e6+10;
ll n, m;
ll a[MX];
vector<ll> lef, rig;
ll LOG2[MX];
ll b[MX], sm[MX], N=0;
ll getSM(int bg, int bm) {
ll tot = 0;
while(bm) {
int rem = bm&-bm;
bm -= rem;
tot += a[LOG2[rem] + bg];
}
return tot;
}
void program() {
IN(n,m);
RE(i,n) IN(a[i]);
RE(i,21) LOG2[(1<<i)] = i;
int mid = n/2;
int len = mid;
RE(bm,(1<<len))
lef.pb(getSM(0,bm));
len = n-mid;
RE(bm,(1<<len))
rig.pb(getSM(mid,bm));
sort(all(lef));
sort(all(rig));
b[0] = -1;
sm[0] = 0;
FOR(p,rig) {
if(b[N] != p) sm[N+1] = sm[N], N++;
b[N] = p;
sm[N]++;
}
N++;
ll ans = 0;
int cur = N-1;
FOR(p,lef) {
ll mx = m - p;
while(b[cur] > mx && cur != 0) cur--;
ans += sm[cur];
}
OUTL(ans);
}
