#include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include using namespace std; using Int = long long; template ostream &operator<<(ostream &os, const pair &a) { return os << "(" << a.first << ", " << a.second << ")"; }; template void pv(T a, T b) { for (T i = a; i != b; ++i) cerr << *i << " "; cerr << endl; } template bool chmin(T &t, const T &f) { if (t > f) { t = f; return true; } return false; } template bool chmax(T &t, const T &f) { if (t < f) { t = f; return true; } return false; } //////////////////////////////////////////////////////////////////////////////// template struct ModInt { static constexpr unsigned M = M_; unsigned x; constexpr ModInt() : x(0U) {} constexpr ModInt(unsigned x_) : x(x_ % M) {} constexpr ModInt(unsigned long long x_) : x(x_ % M) {} constexpr ModInt(int x_) : x(((x_ %= static_cast(M)) < 0) ? (x_ + static_cast(M)) : x_) {} constexpr ModInt(long long x_) : x(((x_ %= static_cast(M)) < 0) ? (x_ + static_cast(M)) : x_) {} ModInt &operator+=(const ModInt &a) { x = ((x += a.x) >= M) ? (x - M) : x; return *this; } ModInt &operator-=(const ModInt &a) { x = ((x -= a.x) >= M) ? (x + M) : x; return *this; } ModInt &operator*=(const ModInt &a) { x = (static_cast(x) * a.x) % M; return *this; } ModInt &operator/=(const ModInt &a) { return (*this *= a.inv()); } ModInt pow(long long e) const { if (e < 0) return inv().pow(-e); ModInt a = *this, b = 1U; for (; e; e >>= 1) { if (e & 1) b *= a; a *= a; } return b; } ModInt inv() const { unsigned a = M, b = x; int y = 0, z = 1; for (; b; ) { const unsigned q = a / b; const unsigned c = a - q * b; a = b; b = c; const int w = y - static_cast(q) * z; y = z; z = w; } assert(a == 1U); return ModInt(y); } ModInt operator+() const { return *this; } ModInt operator-() const { ModInt a; a.x = x ? (M - x) : 0U; return a; } ModInt operator+(const ModInt &a) const { return (ModInt(*this) += a); } ModInt operator-(const ModInt &a) const { return (ModInt(*this) -= a); } ModInt operator*(const ModInt &a) const { return (ModInt(*this) *= a); } ModInt operator/(const ModInt &a) const { return (ModInt(*this) /= a); } template friend ModInt operator+(T a, const ModInt &b) { return (ModInt(a) += b); } template friend ModInt operator-(T a, const ModInt &b) { return (ModInt(a) -= b); } template friend ModInt operator*(T a, const ModInt &b) { return (ModInt(a) *= b); } template friend ModInt operator/(T a, const ModInt &b) { return (ModInt(a) /= b); } explicit operator bool() const { return x; } bool operator==(const ModInt &a) const { return (x == a.x); } bool operator!=(const ModInt &a) const { return (x != a.x); } friend std::ostream &operator<<(std::ostream &os, const ModInt &a) { return os << a.x; } }; //////////////////////////////////////////////////////////////////////////////// //////////////////////////////////////////////////////////////////////////////// // M: prime, G: primitive root, 2^K | M - 1 template struct Fft { static_assert(2U <= M_, "Fft: 2 <= M must hold."); static_assert(M_ < 1U << 30, "Fft: M < 2^30 must hold."); static_assert(1 <= K_, "Fft: 1 <= K must hold."); static_assert(K_ < 30, "Fft: K < 30 must hold."); static_assert(!((M_ - 1U) & ((1U << K_) - 1U)), "Fft: 2^K | M - 1 must hold."); static constexpr unsigned M = M_; static constexpr unsigned M2 = 2U * M_; static constexpr unsigned G = G_; static constexpr int K = K_; ModInt FFT_ROOTS[K + 1], INV_FFT_ROOTS[K + 1]; ModInt FFT_RATIOS[K], INV_FFT_RATIOS[K]; Fft() { const ModInt g(G); for (int k = 0; k <= K; ++k) { FFT_ROOTS[k] = g.pow((M - 1U) >> k); INV_FFT_ROOTS[k] = FFT_ROOTS[k].inv(); } for (int k = 0; k <= K - 2; ++k) { FFT_RATIOS[k] = -g.pow(3U * ((M - 1U) >> (k + 2))); INV_FFT_RATIOS[k] = FFT_RATIOS[k].inv(); } assert(FFT_ROOTS[1] == M - 1U); } // as[rev(i)] <- \sum_j \zeta^(ij) as[j] void fft(ModInt *as, int n) const { assert(!(n & (n - 1))); assert(1 <= n); assert(n <= 1 << K); int m = n; if (m >>= 1) { for (int i = 0; i < m; ++i) { const unsigned x = as[i + m].x; // < M as[i + m].x = as[i].x + M - x; // < 2 M as[i].x += x; // < 2 M } } if (m >>= 1) { ModInt prod = 1U; for (int h = 0, i0 = 0; i0 < n; i0 += (m << 1)) { for (int i = i0; i < i0 + m; ++i) { const unsigned x = (prod * as[i + m]).x; // < M as[i + m].x = as[i].x + M - x; // < 3 M as[i].x += x; // < 3 M } prod *= FFT_RATIOS[__builtin_ctz(++h)]; } } for (; m; ) { if (m >>= 1) { ModInt prod = 1U; for (int h = 0, i0 = 0; i0 < n; i0 += (m << 1)) { for (int i = i0; i < i0 + m; ++i) { const unsigned x = (prod * as[i + m]).x; // < M as[i + m].x = as[i].x + M - x; // < 4 M as[i].x += x; // < 4 M } prod *= FFT_RATIOS[__builtin_ctz(++h)]; } } if (m >>= 1) { ModInt prod = 1U; for (int h = 0, i0 = 0; i0 < n; i0 += (m << 1)) { for (int i = i0; i < i0 + m; ++i) { const unsigned x = (prod * as[i + m]).x; // < M as[i].x = (as[i].x >= M2) ? (as[i].x - M2) : as[i].x; // < 2 M as[i + m].x = as[i].x + M - x; // < 3 M as[i].x += x; // < 3 M } prod *= FFT_RATIOS[__builtin_ctz(++h)]; } } } for (int i = 0; i < n; ++i) { as[i].x = (as[i].x >= M2) ? (as[i].x - M2) : as[i].x; // < 2 M as[i].x = (as[i].x >= M) ? (as[i].x - M) : as[i].x; // < M } } // as[i] <- (1/n) \sum_j \zeta^(-ij) as[rev(j)] void invFft(ModInt *as, int n) const { assert(!(n & (n - 1))); assert(1 <= n); assert(n <= 1 << K); int m = 1; if (m < n >> 1) { ModInt prod = 1U; for (int h = 0, i0 = 0; i0 < n; i0 += (m << 1)) { for (int i = i0; i < i0 + m; ++i) { const unsigned long long y = as[i].x + M - as[i + m].x; // < 2 M as[i].x += as[i + m].x; // < 2 M as[i + m].x = (prod.x * y) % M; // < M } prod *= INV_FFT_RATIOS[__builtin_ctz(++h)]; } m <<= 1; } for (; m < n >> 1; m <<= 1) { ModInt prod = 1U; for (int h = 0, i0 = 0; i0 < n; i0 += (m << 1)) { for (int i = i0; i < i0 + (m >> 1); ++i) { const unsigned long long y = as[i].x + M2 - as[i + m].x; // < 4 M as[i].x += as[i + m].x; // < 4 M as[i].x = (as[i].x >= M2) ? (as[i].x - M2) : as[i].x; // < 2 M as[i + m].x = (prod.x * y) % M; // < M } for (int i = i0 + (m >> 1); i < i0 + m; ++i) { const unsigned long long y = as[i].x + M - as[i + m].x; // < 2 M as[i].x += as[i + m].x; // < 2 M as[i + m].x = (prod.x * y) % M; // < M } prod *= INV_FFT_RATIOS[__builtin_ctz(++h)]; } } if (m < n) { for (int i = 0; i < m; ++i) { const unsigned y = as[i].x + M2 - as[i + m].x; // < 4 M as[i].x += as[i + m].x; // < 4 M as[i + m].x = y; // < 4 M } } const ModInt invN = ModInt(n).inv(); for (int i = 0; i < n; ++i) { as[i] *= invN; } } void fft(vector> &as) const { fft(as.data(), as.size()); } void invFft(vector> &as) const { invFft(as.data(), as.size()); } vector> convolve(vector> as, vector> bs) const { if (as.empty() || bs.empty()) return {}; const int len = as.size() + bs.size() - 1; int n = 1; for (; n < len; n <<= 1) {} as.resize(n); fft(as); bs.resize(n); fft(bs); for (int i = 0; i < n; ++i) as[i] *= bs[i]; invFft(as); as.resize(len); return as; } vector> square(vector> as) const { if (as.empty()) return {}; const int len = as.size() + as.size() - 1; int n = 1; for (; n < len; n <<= 1) {} as.resize(n); fft(as); for (int i = 0; i < n; ++i) as[i] *= as[i]; invFft(as); as.resize(len); return as; } }; const Fft<924844033U, 5U, 21> FFT; constexpr unsigned MO = FFT.M; using Mint = ModInt; constexpr int LIM = 600'010; Mint inv[LIM], fac[LIM], invFac[LIM]; void prepare() { inv[1] = 1; for (int i = 2; i < LIM; ++i) { inv[i] = -((Mint::M / i) * inv[Mint::M % i]); } fac[0] = invFac[0] = 1; for (int i = 1; i < LIM; ++i) { fac[i] = fac[i - 1] * i; invFac[i] = invFac[i - 1] * inv[i]; } } Mint binom(Int n, Int k) { if (n < 0) { if (k >= 0) { return ((k & 1) ? -1 : +1) * binom(-n + k - 1, k); } else if (n - k >= 0) { return (((n - k) & 1) ? -1 : +1) * binom(-k - 1, n - k); } else { return 0; } } else { if (0 <= k && k <= n) { assert(n < LIM); return fac[n] * invFac[k] * invFac[n - k]; } else { return 0; } } } int A, B, C; int main() { prepare(); for (; ~scanf("%d%d%d", &A, &B, &C); ) { assert(0<=A);assert(A<=200'000); assert(0<=B);assert(B<=200'000); assert(0<=C);assert(C<=200'000); Mint ans = 0; if ((A + B + C) % 2 == 0) { const int N = (A + B + C) / 2; for (int rb = 0; rb < 3; ++rb) { const int rc = (B + rb - C + 3) % 3; vector fs(B / 3 + 10, 0); vector gs(C / 3 + 10, 0); for (int i = 0, b; (b = 3 * i + rb) <= B; ++i) fs[i] = invFac[b] * invFac[B - b]; for (int i = 0, c; (c = 3 * i + rc) <= C; ++i) gs[i] = invFac[c] * invFac[C - c]; const auto prod = FFT.convolve(fs, gs); for (int i = 0; i < (int)prod.size(); ++i) { const int a = N - (3 * i + rb + rc); if (0 <= a && a <= A) { ans += invFac[a] * invFac[A - a] * prod[i]; } } } ans *= fac[N]; ans *= fac[N]; /* Mint brt = 0; for (int a = 0; a <= A; ++a) for (int b = 0; b <= B; ++b) for (int c = 0; c <= C; ++c) { if (a + b + c == N && (B + b - C - c) % 3 == 0) { Mint tmp = 1; tmp *= fac[N] * invFac[a] * invFac[b] * invFac[c]; tmp *= fac[N] * invFac[A - a] * invFac[B - b] * invFac[C - c]; brt += tmp; } } cerr<<"brt = "<