#include using namespace std; using int64 = long long; const int mod = 1e9 + 7; //const int mod = 998244353; const int64 infll = (1LL << 62) - 1; const int inf = (1 << 30) - 1; struct IoSetup { IoSetup() { cin.tie(nullptr); ios::sync_with_stdio(false); cout << fixed << setprecision(10); cerr << fixed << setprecision(10); } } iosetup; template< typename T1, typename T2 > ostream &operator<<(ostream &os, const pair< T1, T2 > &p) { os << p.first << " " << p.second; return os; } template< typename T1, typename T2 > istream &operator>>(istream &is, pair< T1, T2 > &p) { is >> p.first >> p.second; return is; } template< typename T > ostream &operator<<(ostream &os, const vector< T > &v) { for(int i = 0; i < (int) v.size(); i++) { os << v[i] << (i + 1 != v.size() ? " " : ""); } return os; } template< typename T > istream &operator>>(istream &is, vector< T > &v) { for(T &in : v) is >> in; return is; } template< typename T1, typename T2 > inline bool chmax(T1 &a, T2 b) { return a < b && (a = b, true); } template< typename T1, typename T2 > inline bool chmin(T1 &a, T2 b) { return a > b && (a = b, true); } template< typename T = int64 > vector< T > make_v(size_t a) { return vector< T >(a); } template< typename T, typename... Ts > auto make_v(size_t a, Ts... ts) { return vector< decltype(make_v< T >(ts...)) >(a, make_v< T >(ts...)); } template< typename T, typename V > typename enable_if< is_class< T >::value == 0 >::type fill_v(T &t, const V &v) { t = v; } template< typename T, typename V > typename enable_if< is_class< T >::value != 0 >::type fill_v(T &t, const V &v) { for(auto &e : t) fill_v(e, v); } template< typename F > struct FixPoint : F { FixPoint(F &&f) : F(forward< F >(f)) {} template< typename... Args > decltype(auto) operator()(Args &&... args) const { return F::operator()(*this, forward< Args >(args)...); } }; template< typename F > inline decltype(auto) MFP(F &&f) { return FixPoint< F >{forward< F >(f)}; } static constexpr uint32_t mul_inv(uint32_t n, int e = 5, uint32_t x = 1) { return e == 0 ? x : mul_inv(n, e - 1, x * (2 - x * n)); } template< uint32_t mod > struct ModInt { using u32 = uint32_t; using u64 = uint64_t; static constexpr u32 inv = mul_inv(mod); static constexpr u32 r2 = -u64(mod) % mod; u32 x; ModInt() : x(0) {} ModInt(const u32 &x) : x(reduce(u64(x) * r2)) {} u32 reduce(const u64 &w) const { return u32(w >> 32) + mod - u32((u64(u32(w) * inv) * mod) >> 32); } ModInt &operator+=(const ModInt &p) { if(int(x += p.x - 2 * mod) < 0) x += 2 * mod; return *this; } ModInt &operator-=(const ModInt &p) { if(int(x -= p.x) < 0) x += 2 * mod; return *this; } ModInt &operator*=(const ModInt &p) { x = reduce(uint64_t(x) * p.x); return *this; } ModInt &operator/=(const ModInt &p) { *this *= p.inverse(); return *this; } ModInt operator+(const ModInt &p) const { return ModInt(*this) += p; } ModInt operator-(const ModInt &p) const { return ModInt(*this) -= p; } ModInt operator*(const ModInt &p) const { return ModInt(*this) *= p; } ModInt operator/(const ModInt &p) const { return ModInt(*this) /= p; } bool operator==(const ModInt &p) const { return get() == p.get(); } bool operator!=(const ModInt &p) const { return get() != p.get(); } int get() const { return reduce(x) % mod; } ModInt pow(int64_t n) const { ModInt ret(1), mul(*this); while(n > 0) { if(n & 1) ret *= mul; mul *= mul; n >>= 1; } return ret; } ModInt inverse() const { return pow(mod - 2); } friend ostream &operator<<(ostream &os, const ModInt &p) { return os << p.get(); } friend istream &operator>>(istream &is, ModInt &a) { int64_t t; is >> t; a = ModInt< mod >(t); return (is); } static int get_mod() { return mod; } }; using modint = ModInt< mod >; int main() { int N, P; cin >> N >> P; vector< modint > S(N); S[0] = 0; S[1] = 1; for(int i = 2; i < N; i++) { S[i] = S[i - 1] * P + S[i - 2]; } modint sum = 0, ret = 0; for(int i = 0; i < N; i++) { sum += S[i]; ret += sum * S[i]; } cout << ret << endl; }