#include using namespace std; #define rep(i, n) for (int i = 0; i < n; i++) #define rep2(i, x, n) for (int i = x; i <= n; i++) #define rep3(i, x, n) for (int i = x; i >= n; i--) #define each(e, v) for (auto &e : v) #define pb push_back #define eb emplace_back #define all(x) x.begin(), x.end() #define rall(x) x.rbegin(), x.rend() #define sz(x) (int)x.size() using ll = long long; using pii = pair; using pil = pair; using pli = pair; using pll = pair; template bool chmax(T &x, const T &y) { return (x < y) ? (x = y, true) : false; } template bool chmin(T &x, const T &y) { return (x > y) ? (x = y, true) : false; } template int flg(T x, int i) { return (x >> i) & 1; } template void print(const vector &v, T x = 0) { int n = v.size(); for (int i = 0; i < n; i++) cout << v[i] + x << (i == n - 1 ? '\n' : ' '); if (v.empty()) cout << '\n'; } template void printn(const vector &v, T x = 0) { int n = v.size(); for (int i = 0; i < n; i++) cout << v[i] + x << '\n'; } template int lb(const vector &v, T x) { return lower_bound(begin(v), end(v), x) - begin(v); } template int ub(const vector &v, T x) { return upper_bound(begin(v), end(v), x) - begin(v); } template void rearrange(vector &v) { sort(begin(v), end(v)); v.erase(unique(begin(v), end(v)), end(v)); } template vector id_sort(const vector &v, bool greater = false) { int n = v.size(); vector ret(n); iota(begin(ret), end(ret), 0); sort(begin(ret), end(ret), [&](int i, int j) { return greater ? v[i] > v[j] : v[i] < v[j]; }); return ret; } template pair operator+(const pair &p, const pair &q) { return make_pair(p.first + q.first, p.second + q.second); } template pair operator-(const pair &p, const pair &q) { return make_pair(p.first - q.first, p.second - q.second); } template istream &operator>>(istream &is, pair &p) { S a; T b; is >> a >> b; p = make_pair(a, b); return is; } template ostream &operator<<(ostream &os, const pair &p) { return os << p.first << ' ' << p.second; } struct io_setup { io_setup() { ios_base::sync_with_stdio(false); cin.tie(NULL); cout << fixed << setprecision(15); } } io_setup; const int inf = (1 << 30) - 1; const ll INF = (1LL << 60) - 1; // const int MOD = 1000000007; const int MOD = 998244353; template struct Mod_Int { int x; Mod_Int() : x(0) {} Mod_Int(long long y) : x(y >= 0 ? y % mod : (mod - (-y) % mod) % mod) {} static int get_mod() { return mod; } Mod_Int &operator+=(const Mod_Int &p) { if ((x += p.x) >= mod) x -= mod; return *this; } Mod_Int &operator-=(const Mod_Int &p) { if ((x += mod - p.x) >= mod) x -= mod; return *this; } Mod_Int &operator*=(const Mod_Int &p) { x = (int)(1LL * x * p.x % mod); return *this; } Mod_Int &operator/=(const Mod_Int &p) { *this *= p.inverse(); return *this; } Mod_Int &operator++() { return *this += Mod_Int(1); } Mod_Int operator++(int) { Mod_Int tmp = *this; ++*this; return tmp; } Mod_Int &operator--() { return *this -= Mod_Int(1); } Mod_Int operator--(int) { Mod_Int tmp = *this; --*this; return tmp; } Mod_Int operator-() const { return Mod_Int(-x); } Mod_Int operator+(const Mod_Int &p) const { return Mod_Int(*this) += p; } Mod_Int operator-(const Mod_Int &p) const { return Mod_Int(*this) -= p; } Mod_Int operator*(const Mod_Int &p) const { return Mod_Int(*this) *= p; } Mod_Int operator/(const Mod_Int &p) const { return Mod_Int(*this) /= p; } bool operator==(const Mod_Int &p) const { return x == p.x; } bool operator!=(const Mod_Int &p) const { return x != p.x; } Mod_Int inverse() const { assert(*this != Mod_Int(0)); return pow(mod - 2); } Mod_Int pow(long long k) const { Mod_Int now = *this, ret = 1; for (; k > 0; k >>= 1, now *= now) { if (k & 1) ret *= now; } return ret; } friend ostream &operator<<(ostream &os, const Mod_Int &p) { return os << p.x; } friend istream &operator>>(istream &is, Mod_Int &p) { long long a; is >> a; p = Mod_Int(a); return is; } }; using mint = Mod_Int; int main() { ll N, K; cin >> N >> K; vector a(N); rep(i, N) cin >> a[i]; vector s = a; rep2(i, 1, N - 1) s[i] += s[i - 1]; // print(s); int M = 20; vector> dp(M, vector(2, 0)), ndp(M, vector(2, 0)); dp[0][0] = 1; rep(i, N) { rep(j, M) rep(k, 2) ndp[j][k] = 0; rep(j, M) { rep(k, 2) { if (dp[j][k] == 0) continue; ll x = -INF; if (j > 0) x = (s[i - j] - 1) << (j - 1); // b[i] = a[i] { int nj = (j == 0 ? 0 : j + 1), nk = k; if (a[i] > x) nj = 0; if (a[i] > 0) nk = 0; if (nj < M) ndp[nj][nk] += dp[j][k]; } // b[i] < a[i] { if (x >= 0) { if (a[i] - 1 > x) { ll l = x + 1, r = a[i] - 1; int nj = 1, nk = 0; if (s[i] - 1 == 0) nk = 1; ndp[nj][nk] += dp[j][k] * max(r - l + 1, 0LL); } if (x > 0) { ll l = 1, r = min(x, a[i] - 1); int nj = j + 1, nk = 0; if (s[i] - 1 >= 2 * x) nj = 1; if (s[i] - 1 == 0) nk = 1; if (nj < M) ndp[nj][nk] += dp[j][k] * max(r - l + 1, 0LL); } { ll l = -K, r = min(0LL, a[i] - 1); int nj = j + 1, nk = k; if (s[i] - 1 >= 2 * x) nj = 1; if (s[i] - 1 == 0) nk = 1; if (nj < M) ndp[nj][nk] += dp[j][k] * max(r - l + 1, 0LL); } } else { if (a[i] - 1 > 0) { ll l = 1, r = a[i] - 1; int nj = 1, nk = 0; if (s[i] - 1 == 0) nk = 1; ndp[nj][nk] += dp[j][k] * max(r - l + 1, 0LL); } if (x < 0) { ll l = max(-K, x + 1), r = min(0LL, a[i] - 1); int nj = 1, nk = k; if (s[i] - 1 == 0) nk = 1; ndp[nj][nk] += dp[j][k] * max(r - l + 1, 0LL); } if (x >= -K) { ll l = -K, r = min(x, a[i] - 1); int nj = j + 1, nk = k; if (s[i] - 1 >= 2 * x) nj = 1; if (s[i] - 1 == 0) nk = 1; if (nj < M) ndp[nj][nk] += dp[j][k] * max(r - l + 1, 0LL); } } } } } swap(dp, ndp); // cout << i << '\n'; // rep(i, N) print(dp[i]); } cout << dp[0][0] << '\n'; }