import java.io.BufferedReader
import java.io.InputStream
import java.io.InputStreamReader
import java.lang.AssertionError
import java.util.*
import kotlin.math.abs
import kotlin.math.max
import kotlin.math.min

val MOD = 1_000_000_007

class Solver(stream: InputStream, private val out: java.io.PrintWriter) {
  private val reader = BufferedReader(InputStreamReader(stream), 32768)

  fun solve() {
    val N = nl()
    val ans = when(N){
      1L -> 12L
      2L -> 65L
      else -> {
        val center = (6*N/2 + 1)
        val half = (6*N+1)*N +
            2*N*N + N*(N-1)/2 + // 2N .. 3N
            N
        half*2 + center
      }

    }
    out.println(ans)
//    val que = ArrayDeque<Triple<Int, Int, Int>>()
//    val N = 11
//    val MAX = 71
//    val visit = Array(MAX){BooleanArray(MAX)}
//    val C = IntArray(N + 1)
//    fun add(x: Int, y: Int, cnt: Int) {
//      if (!visit[x][y]) {
//        visit[x][y] = true
//        que.add(Triple(x, y, cnt))
//        C[cnt]++
//      }
//    }
//    add(MAX/2, MAX/2, 0)
//
//    for (i in 0 until N) {
//      visit.forEach { it.fill(false) }
//      while (que.isNotEmpty() && que.peekFirst().third == i) {
//        val v = que.pollFirst()
//        val tt = arrayOf(intArrayOf(2, 3), intArrayOf(0, 3))
//        for (j in 0 until 2) {
//          for (x in 0 until 2) {
//            for (y in 0 until 2) {
//              for (z in 0 until 2) {
//                val a = if (z == 0) tt[j].clone() else tt[j].reversed().toIntArray()
//                if (x == 1) a[0] *= -1
//                if (y == 1) a[1] *= -1
//                val nx = v.first + a[0]
//                val ny = v.second + a[1]
//                add(nx, ny, v.third + 1)
//              }
//            }
//          }
//        }
//      }
//    }
//
//    debugDim(visit)
//    debug{"${C[N]}"}
  }













































  private val isDebug = try {
    // なんか本番でエラーでる
    System.getenv("MY_DEBUG") != null
  } catch (t: Throwable) {
    false
  }

  private var tokenizer: StringTokenizer? = null
  private fun next(): String {
    while (tokenizer == null || !tokenizer!!.hasMoreTokens()) {
      tokenizer = StringTokenizer(reader.readLine())
    }
    return tokenizer!!.nextToken()
  }

  private fun ni() = next().toInt()
  private fun nl() = next().toLong()
  private fun ns() = next()
  private fun na(n: Int, offset: Int = 0): IntArray {
    return IntArray(n) { ni() + offset }
  }
  private fun nal(n: Int, offset: Int = 0): LongArray {
    val res = LongArray(n)
    for (i in 0 until n) {
      res[i] = nl() + offset
    }
    return res
  }

  private fun na2(n: Int, offset: Int = 0): Array<IntArray> {
    val a  = Array(2){IntArray(n)}
    for (i in 0 until n) {
      for (e in a) {
        e[i] = ni() + offset
      }
    }
    return a
  }

  private inline fun debug(msg: () -> String) {
    if (isDebug) System.err.println(msg())
  }

  /**
   * コーナーケースでエラー出たりするので、debug(dp[1])のように添え字付きの場合はdebug{}をつかうこと
   */
  private inline fun debug(a: LongArray) {
    debug { a.joinToString(" ") }
  }

  private inline fun debug(a: IntArray) {
    debug { a.joinToString(" ") }
  }

  private inline fun debug(a: BooleanArray) {
    debug { toString(a) }
  }

  private inline fun toString(a: BooleanArray) = run{a.map { if (it) 1 else 0 }.joinToString("")}

  private inline fun debugDim(A: Array<LongArray>) {
    if (isDebug) {
      for (a in A) {
        debug(a)
      }
    }
  }
  private inline fun debugDim(A: Array<IntArray>) {
    if (isDebug) {
      for (a in A) {
        debug(a)
      }
    }
  }
  private inline fun debugDim(A: Array<BooleanArray>) {
    if (isDebug) {
      for (a in A) {
        debug(a)
      }
    }
  }

  /**
   * 勝手にimport消されるのを防ぎたい
   */
  private fun hoge() {
    min(1, 2)
    max(1, 2)
    abs(-10)
  }

  private inline fun assert(b: Boolean) = run{if (!b) throw AssertionError()}
  private inline fun assert(b: Boolean, f: () -> String) = run{if (!b) throw AssertionError(f())}
}

fun main() {
  val out = java.io.PrintWriter(System.out)
  Solver(System.`in`, out).solve()
  out.flush()
}