import java.io.PrintWriter import java.lang.Exception import java.util.* data class Matrix(val a: ModInt, val b: ModInt, val c: ModInt, val d: ModInt) fun product(x: Matrix, y: Matrix): Matrix { val a = x.a * y.a + x.b * y.c val b = x.a * y.b + x.b * y.d val c = x.c * y.a + x.d * y.c val d = x.c * y.b + x.d * y.d return Matrix(a, b, c, d) } fun pow(m: Matrix, n: Long): Matrix { if (n == 0L) { return Matrix(ModInt(1), ModInt(0), ModInt(0), ModInt(1)) } else if (n == 1L) { return m } val x = pow(m, n / 2) val y = product(x, x) if (n % 2 == 0L) { return y } else { return product(y, m) } } fun PrintWriter.solve() { val n = nextLong() val a = nextLong() val b = nextLong() val k = nextLong() val c = ModInt(a * a + b * b + k) / ModInt(a * b) val m = pow(Matrix(c, ModInt(-1), ModInt(1), ModInt(0)), n - 1) println(m.c * b.toModInt() + m.d * a.toModInt()) } // region ModInt class ModInt(x: Long) { companion object { const val MOD = 1000000007L //const val MOD = 998244353L } 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" } } fun Long.toModInt(): ModInt { return ModInt(this) } fun Int.toModInt(): ModInt { return ModInt(this) } fun binomSimple(n: Long, k: Long): ModInt { var numer = ModInt(1) var denom = ModInt(1) for (i in 0 until k) { numer *= ModInt(n - i) denom *= ModInt(k - i) } return numer / denom } // endregion fun main() { val writer = PrintWriter(System.out, false) writer.solve() writer.flush() } // region Scanner private var st = StringTokenizer("") private val br = System.`in`.bufferedReader() fun next(): String { while (!st.hasMoreTokens()) st = StringTokenizer(br.readLine()) return st.nextToken() } fun nextInt() = next().toInt() fun nextLong() = next().toLong() fun nextLine() = br.readLine() fun nextDouble() = next().toDouble() // endregion