// No.345 最小チワワ問題
package main

import (
	"fmt"
	"slices"
	"strings"
)

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

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