#pragma region Macros #include #define rep(i, n) for(int(i) = 0; (i) < (n); (i)++) #define rrep(i, n) for(int(i) = (n)-1; (i) >= 0; (i)--) #define FOR(i, m, n) for(int(i) = (m); (i) < (n); (i)++) #define ROF(i, m, n) for(int(i) = (n)-1; (i) >= (m); (i)--) #define ALL(v) (v).begin(), (v).end() #define LLA(v) (v).rbegin(), (v).rend() #define SZ(v) (int)(v).size() #define INT(...) \ int __VA_ARGS__; \ read(__VA_ARGS__) #define LL(...) \ ll __VA_ARGS__; \ read(__VA_ARGS__) #define DOUBLE(...) \ double __VA_ARGS__; \ read(__VA_ARGS__) #define CHAR(...) \ char __VA_ARGS__; \ read(__VA_ARGS__) #define STRING(...) \ string __VA_ARGS__; \ read(__VA_ARGS__) #define VEC(type, name, size) \ vector name(size); \ read(name) #define VEC2(type, name, height, width) \ vector> name(height, vector(width)); \ read(name) #define DVEC(type, name1, name2, size) \ vector name1(size), name2(size); \ read(name1, name2); #define TVEC(type, name1, name2, name3, size) \ vector name1(size), name2(size), name3(size); \ read(name1, name2, name3); using namespace std; using ll = long long; using pii = pair; using pll = pair; const int INF = 1 << 30; const ll LINF = 1LL << 60; const int MOD = 1e9 + 7; const char newl = '\n'; const int dx[] = {1, 0, -1, 0}; const int dy[] = {0, 1, 0, -1}; template inline bool between(T x, T l, T r) { return l <= x && x < r; } template inline vector make_vec(size_t a, T val) { return vector(a, val); } template inline auto make_vec(size_t a, Ts... ts) { return vector(a, make_vec(ts...)); } void read() {} template inline void read(T &a) { cin >> a; } template inline void read(pair &p) { read(p.first), read(p.second); } template inline void read(vector &v) { for(auto &&a : v) read(a); } template inline void read(vector &a, vector &b) { for(int i = 0; i < a.size(); i++) { read(a[i]); read(b[i]); } } template inline void read(vector &a, vector &b, vector &c) { for(int i = 0; i < a.size(); i++) { read(a[i]); read(b[i]); read(c[i]); } } template inline void read(Head &head, Tail &...tail) { read(head), read(tail...); } template void write(const T &a) { cout << a << '\n'; } template void write(const vector &a) { for(int i = 0; i < a.size(); i++) cout << a[i] << (i + 1 == a.size() ? '\n' : ' '); } template void write(const Head &head, const Tail &...tail) { cout << head << ' '; write(tail...); } template void writel(const T &a) { cout << a << '\n'; } template void writel(const vector &a) { for(int i = 0; i < a.size(); i++) cout << a[i] << '\n'; } template void writel(const Head &head, const Tail &...tail) { cout << head << '\n'; write(tail...); } template auto sum(const vector &a) { return accumulate(ALL(a), T(0)); } template auto min(const vector &a) { return *min_element(ALL(a)); } template auto max(const vector &a) { return *max_element(ALL(a)); } template void msort(vector &a, vector &b) { assert(a.size() == b.size()); vector> ab(a.size()); for(int i = 0; i < a.size(); i++) ab[i] = {a[i], b[i]}; sort(ALL(ab)); for(int i = 0; i < a.size(); i++) { a[i] = ab[i].first; b[i] = ab[i].second; } } template void msort(vector &a, vector &b, vector &c) { assert(a.size() == b.size() && b.size() == c.size()); vector> abc(a.size()); for(int i = 0; i < a.size(); i++) abc[i] = {a[i], b[i], c[i]}; sort(ALL(abc)); for(int i = 0; i < a.size(); i++) { a[i] = get<0>(abc[i]); b[i] = get<1>(abc[i]); c[i] = get<2>(abc[i]); } } template inline bool chmax(T &a, U b) { if(a < b) { a = b; return 1; } return 0; } template inline bool chmin(T &a, U b) { if(a > b) { a = b; return 1; } return 0; } inline int bsf(int v) { return __builtin_ctz(v); } // 最下位の1が下から何番目か inline int bsf(ll v) { return __builtin_ctzll(v); } inline int bsr(int v) { return 31 - __builtin_clz(v); } // 最上位の1が下から何番目か inline int bsr(ll v) { return 63 - __builtin_clzll(v); } inline int lsb(int v) { return v & -v; } // 最上位の1だけ残す inline ll lsb(ll v) { return v & -v; } inline int msb(int v) { return 1 << bsr(v); } // 最上位の1だけ残す inline ll msb(ll v) { return 1LL << bsr(v); } struct IO { IO() { ios::sync_with_stdio(false); cin.tie(nullptr); cout << fixed << setprecision(10); } } io; #pragma endregion /* ModInt */ template class ModInt { using u64 = uint_fast64_t; public: u64 val; ModInt(const u64 x = 0) : val((x + MOD) % MOD) {} constexpr u64 &value() { return val; } static const u64 get_mod() { return MOD; } constexpr ModInt operator-() { return val ? MOD - val : 0; } constexpr ModInt operator+(const ModInt &rhs) const { return ModInt(*this) += rhs; } constexpr ModInt operator-(const ModInt &rhs) const { return ModInt(*this) -= rhs; } constexpr ModInt operator*(const ModInt &rhs) const { return ModInt(*this) *= rhs; } constexpr ModInt operator/(const ModInt &rhs) const { return ModInt(*this) /= rhs; } constexpr ModInt &operator+=(const ModInt &rhs) { val += rhs.val; if(val >= MOD) { val -= MOD; } return *this; } constexpr ModInt &operator-=(const ModInt &rhs) { if(val < rhs.val) { val += MOD; } val -= rhs.val; return *this; } constexpr ModInt &operator*=(const ModInt &rhs) { val = val * rhs.val % MOD; return *this; } constexpr ModInt &operator/=(const ModInt &rhs) { *this *= rhs.inv(); return *this; } constexpr bool operator==(const ModInt &rhs) { return this->val == rhs.val; } constexpr bool operator!=(const ModInt &rhs) { return this->val != rhs.val; } friend constexpr ostream &operator<<(ostream &os, const ModInt &x) { return os << x.val; } friend constexpr istream &operator>>(istream &is, ModInt &x) { return is >> x.val; } constexpr ModInt inv() const { return ModInt(*this).pow(MOD - 2); } constexpr ModInt pow(long long e) const { u64 x = 1, p = val; while(e > 0) { if(e % 2 == 0) { p = (p * p) % MOD; e /= 2; } else { x = (x * p) % MOD; e--; } } return ModInt(x); } }; using mint = ModInt; int main() { INT(n, k); write((mint(n).pow(k) - (mint(n - 1)).pow(k)) * n); }