Today Adilbek is taking his probability theory test. Unfortunately, when Adilbek arrived at the university, there had already been a long queue of students wanting to take the same test. Adilbek has estimated that he will be able to start the test only T seconds after coming. 

Fortunately, Adilbek can spend time without revising any boring theorems or formulas. He has an app on this smartphone which contains n Japanese crosswords to solve. Adilbek has decided to solve them all one by one in the order they are listed in the app, without skipping any crossword. For each crossword, a number t_i is given that represents the time it takes an average crossword expert to solve this crossword (the time is given in seconds).

Adilbek is a true crossword expert, but, unfortunately, he is sometimes unlucky in choosing the way to solve the crossword. So, it takes him either t_i seconds or t_i + 1 seconds to solve the i-th crossword, equiprobably (with probability 1/2 he solves the crossword in exactly t_i seconds, and with probability 1/2 he has to spend an additional second to finish the crossword). All these events are independent.

After T seconds pass (or after solving the last crossword, if he manages to do it in less than T seconds), Adilbek closes the app (if he finishes some crossword at the same moment, that crossword is considered solved; otherwise Adilbek does not finish solving the current crossword at all). He thinks it would be an interesting probability theory problem to calculate E — the expected number of crosswords he will be able to solve completely. Can you calculate it? 

Recall that the expected value of a discrete random variable is the probability-weighted average of all possible values — in this problem it means that the expected value of the number of solved crosswords can be calculated as E = ∑ _{i = 0}^{n} i p_i, where p_i is the probability that Adilbek will solve exactly i crosswords. 

We can represent E as rational fraction P/Q with Q > 0. To give the answer, you should print P ⋅ Q^{-1} mod (10^9 + 7).

Input

The first line contains two integers n and T (1 ≤ n ≤ 2 ⋅ 10^5, 1 ≤ T ≤ 2 ⋅ 10^{14}) — the number of crosswords and the time Adilbek has to spend, respectively.

The second line contains n integers t_1, t_2, ..., t_n (1 ≤ t_i ≤ 10^9), where t_i is the time it takes a crossword expert to solve the i-th crossword.

Note that Adilbek solves the crosswords in the order they are given in the input without skipping any of them.

Output

Print one integer — the expected value of the number of crosswords Adilbek solves in T seconds, expressed in the form of P ⋅ Q^{-1} mod (10^9 + 7).

Examples

Input


3 5
2 2 2


Output


750000007


Input


3 5
2 1 2


Output


125000003

Note

The answer for the first sample is equal to 14/8.

The answer for the second sample is equal to 17/8.
#include <bits/stdc++.h>
inline long long gcd(long long a, long long b) { return b ? gcd(b, a % b) : a; }
inline void sub(long long &a, long long b) {
  a -= b;
  if (a < 0) a += 1000000007;
}
inline void add(long long &a, long long b) {
  a += b;
  if (a >= 1000000007) a -= 1000000007;
}
template <typename T>
inline T const &MAX(T const &a, T const &b) {
  return a > b ? a : b;
}
template <typename T>
inline T const &MIN(T const &a, T const &b) {
  return a < b ? a : b;
}
inline long long mul(long long a, long long b, long long c) {
  return (a * b - (long long)((long double)a * b / c) * c + c) % c;
}
inline long long qp(long long a, long long b) {
  long long ans = 1;
  while (b) {
    if (b & 1) ans = ans * a % 1000000007;
    a = a * a % 1000000007, b >>= 1;
  }
  return ans;
}
inline long long qp(long long a, long long b, long long c) {
  long long ans = 1;
  while (b) {
    if (b & 1) ans = mul(ans, a, c);
    a = mul(a, a, c), b >>= 1;
  }
  return ans;
}
using namespace std;
const long double pi = acos(-1);
const unsigned long long ba = 233;
const double eps = 1e-5;
const long long INF = 0x3f3f3f3f3f3f3f3f;
const int N = 200000 + 10, maxn = 2000000 + 10, inf = 0x3f3f3f3f;
long long a[N], f[N], inv[N], po[N];
long long c(int a, int b) {
  if (a < 0 || a < b) return 0;
  return f[a] * inv[b] % 1000000007 * inv[a - b] % 1000000007;
}
int main() {
  f[0] = inv[0] = po[0] = 1;
  for (int i = 1; i < N; i++)
    f[i] = f[i - 1] * i % 1000000007,
    inv[i] = inv[i - 1] * qp(i, 1000000007 - 2) % 1000000007,
    po[i] = po[i - 1] * 2 % 1000000007;
  int n;
  long long t;
  scanf("%d%lld", &n, &t);
  for (int i = 1; i <= n; i++) scanf("%lld", &a[i]), a[i] += a[i - 1];
  long long ans = 0, now = 1, k = 0;
  for (int i = 1; i <= n; i++) {
    if (a[i] > t)
      break;
    else if (a[i] + i <= t) {
      add(ans, 1);
      now = now * 2 % 1000000007, sub(now, c(i - 1, k));
    } else {
      long long x = t - a[i];
      now = now * 2 % 1000000007;
      sub(now, c(i - 1, k));
      while (k > x) sub(now, c(i, k--));
      while (k < x) add(now, c(i, ++k));
      add(ans, now * qp(po[i], 1000000007 - 2) % 1000000007);
    }
  }
  printf("%lld\n", ans);
  return 0;
}
