#pragma region Macros // #pragma GCC target("avx,avx2,fma") // #pragma GCC optimize("O3") // #pragma GCC optimize("unroll-loops") #include // #include using namespace std; using namespace __gnu_pbds; // using namespace __gnu_cxx; // #include // #include // #include // using namespace atcoder; // #include // namespace mp = boost::multiprecision; // using Bint = mp::cpp_int; #define TO_STRING(var) # var #define pb emplace_back #define int ll #define endl '\n' using ll = long long; using ld = long double; const ld PI = acos(-1); const ld EPS = 1e-10; const ll INFL = 1LL << 61; // const int MOD = 998244353; const int MOD = 1000000007; __attribute__((constructor)) void constructor() { ios::sync_with_stdio(false); cin.tie(nullptr); cout << fixed << setprecision(15); } template class modint{ public: int val = 0; modint(int x = 0) { while (x < 0) x += mod; val = x % mod; } modint(const modint &r) { val = r.val; } // コピーコンストラクタ modint operator -(){ return modint(-val); } // 単項 modint operator +(const modint &r) { return modint(*this) += r; } modint operator -(const modint &r) { return modint(*this) -= r; } modint operator *(const modint &r) { return modint(*this) *= r; } modint operator /(const modint &r) { return modint(*this) /= r; } modint &operator +=(const modint &r) { val += r.val; if (val >= mod) val -= mod; return *this; } modint &operator -=(const modint &r) { if (val < r.val) val += mod; val -= r.val; return *this; } modint &operator *=(const modint &r) { val = val * r.val % mod; return *this; } modint &operator /=(const modint &r) { int a = r.val, b = mod, u = 1, v = 0; while (b) { int 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; } bool operator ==(const modint& r) { return this -> val == r.val; } bool operator <(const modint& r) { return this -> val < r.val; } bool operator !=(const modint& r) { return this -> val != r.val; } }; using mint = modint; istream &operator >>(istream &is, mint& x) { int t; is >> t; x = t; return (is); } ostream &operator <<(ostream &os, const mint& x) { return os << x.val; } mint modpow(const mint &a, int n) { if (n == 0) return 1; mint t = modpow(a, n / 2); t = t * t; if (n & 1) t = t * a; return t; } int modpow(int x, int N, int mod) { int ret = 1; while (N > 0) { if (N % 2 == 1) ret = ret * x % mod; x = x * x % mod; N /= 2; } return ret; } int ceil(int x, int y) { return (x > 0 ? (x + y - 1) / y : x / y); } #pragma endregion signed main() { int N, H, W; cin >> N >> H >> W; int a = N / 2; int b = N - a; int ans = (H + W - 2) * a * b; cout << ans << endl; }