import java.io.PrintWriter import java.util.* import kotlin.math.* fun PrintWriter.solve() { val n = nextInt() if (n <= 3) { println(0) return } val dp = Array(n + 1) { Array(2) { Array(2) { Array(2) { ModInt(0) } } } } for (j1 in 0 until 2) { for (j2 in 0 until 2) { for (j3 in 0 until 2) { dp[3][j1][j2][j3] = ModInt(1) } } } for (i in 4 until n + 1) { for (j1 in 0 until 2) { for (j2 in 0 until 2) { for (j3 in 0 until 2) { if (!(j1 == 1 && j2 == 0 && j3 == 1)) { dp[i][j2][j3][0] += dp[i - 1][j1][j2][j3] } dp[i][j2][j3][1] += dp[i - 1][j1][j2][j3] } } } } var sum = ModInt(0) for (j1 in 0 until 2) { for (j2 in 0 until 2) { for (j3 in 0 until 2) { sum += dp[n][j1][j2][j3] } } } println(ModInt(2).pow(n.toLong()) - sum) } // 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" } } 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() { Thread(null, { val writer = PrintWriter(System.out, false) writer.solve() writer.flush() }, "solve", abs(1L.shl(26))) .apply { setUncaughtExceptionHandler { _, e -> e.printStackTrace(); kotlin.system.exitProcess(1) } } .apply { start() }.join() } // 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