func getSum(s: String) -> Int {
  var sum = 0
  (s+"a").characters.reduce("") {
    guard Int(String($1)) == nil else { return "\($0)\($1)" }
    if let cur = Int($0) {
      if cur % 2 == 1 { sum += Int(pow(Double(cur), 2.0)) }
      return ""
    } else { return $0 }
  }
  return sum
}

getSum(s: "ab2v9bc13j5jf4jv21")