package main

import (
	"bufio"
	"fmt"
	"os"
	"regexp"
)

var sc = bufio.NewScanner(os.Stdin)
var rdr = bufio.NewReaderSize(os.Stdin, 1000000)

func main() {
	sc.Split(bufio.ScanWords)
	s := nextLine()
	r := regexp.MustCompile(`c[^c]*?w.*?w`)
	min := 100

	for i := 0; i < len(s); i++ {
		m := r.FindString(s[i:])
		if len(m) < min && len(m) != 0 {
			min = len(m)
		}
	}

	if min == 100 {
		min = -1
	}
	fmt.Println(min)
}

func nextLine() string {
	sc.Scan()
	return sc.Text()
}