fun main() { val facSize = 600000 val arrFac = Array(facSize) { ModInt(1) } val arrInvfac = Array(facSize) { ModInt(1) } for (i in 1 until facSize) { arrFac[i] = arrFac[i - 1] * ModInt(i) } arrInvfac[facSize - 1] = arrFac[facSize - 1].inv() for (i in facSize - 2 downTo 1) { arrInvfac[i] = arrInvfac[i + 1] * ModInt(i + 1) } fun binom(n: Long, k: Long): ModInt { return if (k in 0..n) { arrFac[n.toInt()] * arrInvfac[k.toInt()] * arrInvfac[(n - k).toInt()] } else { ModInt(0) } } val (n, l, u) = readLongs() var ans = ModInt(0) for (m in l..u) { ans += binom(2 * n + m - 1, n - 1) - binom(2 * n + m - 1, n + u + 1) } println(ans) } // region ModInt class ModInt(x: Long) { companion object { const val MOD = 998244353L //const val MOD = 1000000007L } constructor(y: Int) : this(y.toLong()) val x = (x % MOD + MOD) % MOD operator fun plus(other: ModInt): ModInt { return ModInt(x + other.x) } operator fun minus(other: ModInt): ModInt { return ModInt(x - other.x) } operator fun times(other: ModInt): ModInt { return ModInt(x * other.x) } operator fun div(other: ModInt): ModInt { return this * other.inv() } fun pow(exp: Long): ModInt { if (exp == 0L) return ModInt(1L) var a = pow(exp shr 1) a *= a if (exp and 1L == 0L) return a return this * a } fun inv(): ModInt { return this.pow(MOD - 2) } override fun equals(other: Any?): Boolean { if (this === other) return true if (javaClass != other?.javaClass) return false other as ModInt if (x != other.x) return false return true } override fun hashCode(): Int { return x.hashCode() } override fun toString(): String { return "$x" } } // endregion fun readLongs() = readln().split(" ").map { it.toLong() }