#pragma GCC optimize("Ofast") #include #include #include using namespace std; using namespace __gnu_pbds; using ll = long long; using ull = unsigned long long; using pii = pair; using pll = pair; #define rep(i, n) for(int i = 0; i < (n); ++i) #define all(x) (x).begin(),(x).end() constexpr char ln = '\n'; constexpr long long MOD = 1000000007LL; //constexpr long long MOD = 998244353LL; template inline bool chmax(T &a, U b) { if (a < b) { a = b; return true;} return false; } template inline bool chmin(T &a, U b) { if (a > b) { a = b; return true;} return false; } //////////////////////////////////////////////////////////////////////////////////////////////////////////// template struct ModInt { using u64 = std::uint_fast64_t; u64 a; constexpr ModInt(const long long x = 0) noexcept : a(x >= 0 ? x % Modulus : (Modulus - (-x) % Modulus) % Modulus) {} constexpr u64 &value() noexcept { return a; } constexpr const u64 &value() const noexcept { return a; } constexpr ModInt operator+(const ModInt rhs) const noexcept {return ModInt(*this) += rhs;} constexpr ModInt operator-(const ModInt rhs) const noexcept {return ModInt(*this) -= rhs;} constexpr ModInt operator*(const ModInt rhs) const noexcept {return ModInt(*this) *= rhs;} constexpr ModInt operator/(const ModInt rhs) const noexcept {return ModInt(*this) /= rhs;} constexpr ModInt operator^(const long long rhs) const noexcept {return ModInt(*this) ^= rhs;} constexpr ModInt &operator+=(const ModInt rhs) noexcept { a += rhs.a; if (a >= Modulus) { a -= Modulus; } return *this; } constexpr ModInt &operator-=(const ModInt rhs) noexcept { if (a < rhs.a) { a += Modulus; } a -= rhs.a; return *this; } constexpr ModInt &operator*=(const ModInt rhs) noexcept { a = a * rhs.a % Modulus; return *this; } constexpr ModInt &operator/=(ModInt rhs) noexcept { u64 exp = Modulus - 2; while (exp) { if (exp&1) *this *= rhs; exp >>= 1; rhs *= rhs; } return *this; } constexpr ModInt &operator^=(long long exp) noexcept { ModInt rhs = a; a = 1; while (exp) { if (exp&1) *this *= rhs; exp >>= 1; rhs *= rhs; } return *this; } bool operator==(const ModInt &p) const {return a == p.a;} bool operator!=(const ModInt &p) const {return a != p.a;} }; using mint = ModInt; struct ModCombination { vector Fac; vector Facinv; ModCombination(int x) { Fac.resize(x+1); Facinv.resize(x+1); Fac[0] = 1; for (int i = 0; i < x; ++i) Fac[i+1] = Fac[i]*(i+1); Facinv[x] = Fac[0]/Fac[x]; for (int i = x; i > 0; --i) Facinv[i-1] = Facinv[i]*i; } mint get(int n, int k) { if (k < 0 || k > n) return 0; return Fac[n]*Facinv[k]*Facinv[n-k]; } }; int main() { ios::sync_with_stdio(false); cin.tie(nullptr); int N,M,K; cin >> N >> M >> K; ModCombination MC(N+M); mint ans = 0; for (int i = K; i <= N+M; i++) { if (N-M+i >= 0 and (N-M+i)%2==0) { int num = (N-M+i)/2; if (N - num < 1 or M - (i - num) < 1 or i - num < 0) continue; int n = N - num; ans += MC.get(N-1,n-1)*MC.get(M-1,n-1)/n; } } ans *= MC.Fac[N]*MC.Fac[M]; cout << ans.a << ln; }