Hackerrank Is Fibo in scala

Is Fibo.scala

import scala.math.BigInt
object Solution {
  def main(args: Array[String]) = {
    def fibFrom(a: BigInt, b: BigInt): Stream[BigInt] = a #:: fibFrom(b, a + b)
    val lines = io.Source.stdin.getLines.drop(1).toList
    val nums:List[BigInt] = lines.map( l => BigInt(l))
    def isFib(n: BigInt):String = {
      val fs = fibFrom(0,1).takeWhile(f => f <= n).toList
      if (fs.last < n ) "IsNotFibo" else "IsFibo"
    }
    nums.foreach( n => println(isFib(n)))
  }
}