import math._

object Main {
  def main(args: Array[String]) = {
    val sc = new java.util.Scanner(System.in)
    val s = sc.next

    val reg = "c.*?w.*?w".r
    var ans = Integer.MAX_VALUE
    for (i <- 0 to s.length-1 if s(i) == 'c') {
      reg.findFirstIn(s.substring(i)) match {
        case Some(v) => ans = min(ans, v.length)
        case _ =>
      }
    }

    if (ans == Integer.MAX_VALUE)
      println(-1)
    else
      println(ans)
  }
}