// No.345 最小チワワ問題
package main

import (
	"fmt"
	"strings"
)

func main() {
	var s string
	fmt.Scan(&s)

	var target string = ""
	for i, r := range s {
		if string(r) == "c" && strings.Count(s[i:], "w") >= 2 {
			target = s[i:]
		}
	}
	if target == "" {
		fmt.Println(-1)
	} else {
		w := strings.SplitAfterN(target, "w", 3)
		fmt.Println(len(w[0]) + len(w[1]))
	}
}