#include using namespace std; using i64 = long long; #define rep(i,s,e) for(i64 (i) = (s);(i) < (e);(i)++) #define all(x) x.begin(),x.end() #define STRINGIFY(n) #n #define TOSTRING(n) STRINGIFY(n) #define PREFIX "#" TOSTRING(__LINE__) "| " #define debug(x) \ { \ std::cout << PREFIX << #x << " = " << x << std::endl; \ } std::ostream& output_indent(std::ostream& os, int ind) { for(int i = 0; i < ind; i++) os << " "; return os; } template std::ostream& operator<<(std::ostream& os, const std::pair& p); template std::ostream& operator<<(std::ostream& os, const std::vector& v); template std::ostream& operator<<(std::ostream& os, const std::pair& p) { return (os << "(" << p.first << ", " << p.second << ")"); } template std::ostream& operator<<(std::ostream& os, const std::vector& v) { os << "["; for(int i = 0;i < v.size();i++) os << v[i] << ", "; return (os << "]"); } template static inline std::vector ndvec(size_t&& n, T val) { return std::vector(n, std::forward(val)); } template static inline auto ndvec(size_t&& n, Tail&&... tail) { return std::vector(tail)...))>(n, ndvec(std::forward(tail)...)); } i64 gcd(i64 a, i64 b) { if(b == 0) return a; return gcd(b, a % b); } #include using i64 = long long; template struct modint { i64 a; constexpr modint(const i64 x = 0): a((x%M+M)%M){} constexpr i64 value() const { return a; } constexpr modint inv() const { return this->pow(M-2); } constexpr modint pow(i64 r) const { modint ans(1); modint aa = *this; while(r) { if(r & 1) ans *= aa; aa *= aa; r >>= 1; } return ans; } constexpr modint& operator=(const i64 r) { a = (r % M + M) % M; return *this; } constexpr modint& operator+=(const modint r) { a += r.a; if(a >= M) a -= M; return *this; } constexpr modint& operator-=(const modint r) { a -= r.a; if(a < 0) a += M; return *this; } constexpr modint& operator*=(const modint r) { a = a * r.a % M; return *this; } constexpr modint& operator/=(const modint r) { (*this) *= r.inv(); return *this; } constexpr modint operator+(const modint r) const { return modint(*this) += r; } constexpr modint operator-(const modint r) const { return modint(*this) -= r; } constexpr modint operator*(const modint r) const { return modint(*this) *= r; } constexpr modint operator/(const modint r) const { return modint(*this) /= r; } constexpr bool operator!=(const modint r) const { return this->value() != r.value(); } }; template std::ostream& operator<<(std::ostream& os, const modint& m) { os << m.value(); return os; } using fp = modint<998244353>; int main() { i64 N, X, Y; cin >> N >> X >> Y; { i64 a = std::min(X, Y); i64 b = std::max(X, Y); X = a; Y = b; } // down hill i64 c; if(X == 1) { c = X; } else { c = X + 1; } if(c == Y) { if(Y == N) { cout << 1 << endl; } else { cout << 0 << endl; } return 0; } if(Y == N) { Y++; } vector dp(Y - c, fp(0)); dp[0] = fp(1); rep(i,1,dp.size()) { dp[i] += dp[i - 1]; if(i - 3 >= 0) { dp[i] += dp[i - 3]; } } cout << dp.back() << endl; }