#pragma target("avx") #include using namespace std; template class modint { using u64 = std::uint_fast64_t; public: u64 a; constexpr modint(const u64 x = 0) noexcept : a(x % Modulus) {} constexpr u64 &value() noexcept { return a; } constexpr const u64 &value() const noexcept { return a; } constexpr modint operator+(const modint rhs) const noexcept { return modint(*this) += rhs; } constexpr modint operator-(const modint rhs) const noexcept { return modint(*this) -= rhs; } constexpr modint operator*(const modint rhs) const noexcept { return modint(*this) *= rhs; } constexpr modint operator/(const modint rhs) const noexcept { return modint(*this) /= rhs; } constexpr modint &operator+=(const modint rhs) noexcept { a += rhs.a; if (a >= Modulus) { a -= Modulus; } return *this; } constexpr modint &operator-=(const modint rhs) noexcept { if (a < rhs.a) { a += Modulus; } a -= rhs.a; return *this; } constexpr modint &operator*=(const modint rhs) noexcept { a = a * rhs.a % Modulus; return *this; } constexpr modint &operator/=(modint rhs) noexcept { u64 exp = Modulus - 2; while (exp) { if (exp % 2) { *this *= rhs; } rhs *= rhs; exp /= 2; } return *this; } }; typedef long long ll; typedef long double ld; typedef pair P; typedef vector V; typedef unordered_map U_MAP; typedef priority_queue pq; typedef priority_queue, greater> rpq; const int INF = 1e9, MOD = 1e9 + 7, ohara = 1e6 + 10; const ll LINF = 1e18; #define rep(i, n) for (ll(i) = 0; (i) < (int)(n); (i)++) #define rrep(i, a, b) for (ll i = (a); i < (b); i++) #define rrrep(i, a, b) for (ll i = (a); i >= (b); i--) #define all(v) (v).begin(), (v).end() #define Size(n) (n).size() #define Cout(x) cout << (x) << endl #define doublecout(a) cout << fixed << setprecision(15) << a << endl; #define fi first #define se second #define m_p make_pair #define p_b push_back string to_string(string s) { return '"' + s + '"'; } string to_string(const char *s) { return to_string((string)s); } string to_string(bool b) { return (b ? "true" : "false"); } template string to_string(pair p) { return "(" + to_string(p.first) + ", " + to_string(p.second) + ")"; } template string to_string(A v) { bool first = true; string res = "{"; for (const auto &x : v) { if (!first) { res += ", "; } first = false; res += to_string(x); } res += "}"; return res; } void debug_out() { cerr << endl; } template void debug_out(Head H, Tail... T) { cerr << " " << to_string(H); debug_out(T...); } #define debug(...) cerr << "[" << #__VA_ARGS__ << "]:", debug_out(__VA_ARGS__) //------ Believe yourself as a genius!!!!!! ------ int dy[] = {1, 0, -1, 0}; int dx[] = {0, 1, 0, -1}; // int dy[]={-1,0,1,-1,1,-1,0,1};int dx[]={-1,-1,-1,0,0,1,1,1}; string alph("abcdefghijklmnopqrstuvwxyz"), s; ll n, cnt, ans, a[ohara], b, c, d, tmp, m, h, w, x, y, k, q, p; ll gen; int main(void) { cin.tie(0); cout.tie(0); ios::sync_with_stdio(false); using mint = modint; cin >> n >> p; a[0] = 0; a[1] = 1; rrep(i, 2, n) { a[i] = p * a[i - 1] + a[i - 2]; a[i] %= MOD; } mint sum = mint(0), gen = mint(0); rep(i, n) { sum += (mint)a[i]; } sum = sum * sum; rep(i, n) { gen += (mint)(a[i] * a[i]); } gen = sum - gen; gen /= 2; sum -= gen; Cout(sum.value()); return 0; }