#include using namespace std; typedef long long ll; typedef pair P; #define DUMP(x) cout << #x << " = " << (x) << endl; #define FOR(i, m, n) for (ll i = m; i < n; i++) #define IFOR(i, m, n) for (ll i = n - 1; i >= m; i--) #define REP(i, n) FOR(i, 0, n) #define IREP(i, n) IFOR(i, 0, n) #define FOREACH(x, a) for (auto&(x) : (a)) #define ALL(v) (v).begin(), (v).end() #define SZ(x) ll(x.size()) template struct Fp { long long val; constexpr Fp(long long v = 0) noexcept : val(v % MOD) { if (val < 0) val += MOD; } constexpr int getmod() { return MOD; } constexpr Fp operator-() const noexcept { return val ? MOD - val : 0; } constexpr Fp operator+(const Fp& r) const noexcept { return Fp(*this) += r; } constexpr Fp operator-(const Fp& r) const noexcept { return Fp(*this) -= r; } constexpr Fp operator*(const Fp& r) const noexcept { return Fp(*this) *= r; } constexpr Fp operator/(const Fp& r) const noexcept { return Fp(*this) /= r; } constexpr Fp& operator+=(const Fp& r) noexcept { val += r.val; if (val >= MOD) val -= MOD; return *this; } constexpr Fp& operator-=(const Fp& r) noexcept { val -= r.val; if (val < 0) val += MOD; return *this; } constexpr Fp& operator*=(const Fp& r) noexcept { val = val * r.val % MOD; return *this; } constexpr Fp& operator/=(const Fp& r) noexcept { long long a = r.val, b = MOD, u = 1, v = 0; while (b) { long long t = a / b; a -= t * b; swap(a, b); u -= t * v; swap(u, v); } val = val * u % MOD; if (val < 0) val += MOD; return *this; } constexpr bool operator==(const Fp& r) const noexcept { return this->val == r.val; } constexpr bool operator!=(const Fp& r) const noexcept { return this->val != r.val; } friend constexpr ostream& operator<<(ostream& os, const Fp& x) noexcept { return os << x.val; } friend constexpr Fp modpow(const Fp& a, long long n) noexcept { if (n == 0) return 1; auto t = modpow(a, n / 2); t = t * t; if (n & 1) t = t * a; return t; } }; // 二項係数ライブラリ template struct BiCoef { vector fact_, inv_, finv_; constexpr BiCoef() {} constexpr BiCoef(int n) noexcept : fact_(n, 1), inv_(n, 1), finv_(n, 1) { init(n); } constexpr void init(int n) noexcept { fact_.assign(n, 1), inv_.assign(n, 1), finv_.assign(n, 1); int MOD = fact_[0].getmod(); for (int i = 2; i < n; i++) { fact_[i] = fact_[i - 1] * i; inv_[i] = -inv_[MOD % i] * (MOD / i); finv_[i] = finv_[i - 1] * inv_[i]; } } constexpr T com(int n, int k) const noexcept { if (n < k || n < 0 || k < 0) return 0; return fact_[n] * finv_[k] * finv_[n - k]; } constexpr T fact(int n) const noexcept { if (n < 0) return 0; return fact_[n]; } constexpr T inv(int n) const noexcept { if (n < 0) return 0; return inv_[n]; } constexpr T finv(int n) const noexcept { if (n < 0) return 0; return finv_[n]; } // C(n,k), n <= 1e9, k <= 1e6 constexpr T com2(int n, int k) const noexcept { if (n < k || n < 0 || k < 0) return 0; T res = 1; for (int i = n; i >= n - k + 1; i--) { T a = i, b = i - n + k; res *= a / b; } return res; } }; const int MOD = 1000000007; using mint = Fp; BiCoef bc; // 二項係数Library使用時はmain内で初期化を忘れないこと // int main(){ // bc.init(2100000); // } int main() { ll p, k; cin >> p >> k; vector> dp(2, vector(2, 0)); dp[0][0] = 1; REP(i, k) { ll j = i % 2; ll nj = j ^ 1; dp[nj][0] = dp[j][1] * 2 + dp[j][0] * (p + 1); dp[nj][1] = dp[j][0] * (p - 1) + dp[j][1] * 2 * (p - 1); // REP(m, 2) { cout << dp[nj][0] << " " << dp[nj][1] << endl; } } cout << dp[k % 2][0] << endl; }