#pragma GCC optimize ("O2") #pragma GCC target ("avx2") #include using namespace std; typedef long long ll; #define rep(i, n) for(int i = 0; i < (n); i++) #define rep1(i, n) for(int i = 1; i <= (n); i++) #define co(x) cout << (x) << "\n" #define cosp(x) cout << (x) << " " #define ce(x) cerr << (x) << "\n" #define cesp(x) cerr << (x) << " " #define pb push_back #define mp make_pair #define chmin(x, y) x = min(x, y) #define chmax(x, y) x = max(x, y) #define Would #define you #define please const int mod = 1e9 + 7; const int IMAX = 200000; constexpr ll modpow(ll A, ll B) { ll kotae = 1; while (B > 0) { if (B & 1) kotae = kotae * A % mod; A = A * A % mod; B >>= 1; } return kotae; } class unko { public: int fac[IMAX + 1], ifac[IMAX + 1], inv[IMAX + 1]; unko() : fac(), ifac(), inv() { fac[0] = 1; rep1(i, IMAX) fac[i] = ll(fac[i - 1]) * i % mod; ifac[IMAX] = modpow(fac[IMAX], mod - 2); for (int i = IMAX; i > 0; i--) ifac[i - 1] = ll(ifac[i]) * i % mod; inv[0] = 1; rep1(i, IMAX) inv[i] = ll(ifac[i]) * fac[i - 1] % mod; } int comb(int A, int B) { return ll(fac[A]) * ifac[B] % mod * ifac[A - B] % mod; } } f; int main() { cin.tie(0); ios::sync_with_stdio(false); ll N, K; cin >> N >> K; ll kotae = 0; ll kari = modpow(K % mod, N); ll usiro = (K + 1) % mod; usiro = usiro * modpow(2, mod - 2) % mod; rep(i, N) { ll tmp = f.comb(N, i); kotae = (kotae + kari * tmp % mod) % mod; kari = kari * usiro % mod; } co(kotae% mod); Would you please return 0; }