object Main {

    def solve(s: String): Int = {
        val n = s.length
        var answer, w1, w2 = Int.MaxValue
        for (idx <- (n - 1) to 0 by -1) {
            if (s(idx) == 'w') {
                w2 = w1
                w1 = idx
            } else if (s(idx) == 'c' && w2 < Int.MaxValue) {
                answer = scala.math.min(answer, w2 - idx + 1)
            }
        }
        if (answer < Int.MaxValue) {
            return answer
        } else {
            return -1
        }
    }

    def main(args: Array[String]): Unit = {
        println(solve(scala.io.StdIn.readLine()))
    }

}