package main

import (
	"bufio"
	"fmt"
	"math"
	"os"
)

type myScanner struct {
	*bufio.Scanner
}

func NewScanner(fp *os.File) *myScanner {
	return &myScanner{
		bufio.NewScanner(fp),
	}
}
func (sc *myScanner) nextLine() (bool, string) {
	flg := sc.Scan()
	return !flg, sc.Text()
}

func check(in string) bool {
	c, w := false, false
	for _, s := range in {
		if s == 'c' {
			c = true
			continue
		}
		if c && !w && s == 'w' {
			w = true
			continue
		}
		if c && w && s == 'w' {
			return true
		}
	}
	return false
}

func cww(in string) int {
	min := math.MaxInt64
	c, w := -1, -1
	for i, s := range in {
		switch s {
		case 'c':
			c = i
		case 'w':
			if w != -1 {
				min = int(math.Min(float64(min), float64(i-w)+1))
			} else if c != -1 {
				// 起点となるcの位置を保持
				w = c
			}
		}
	}
	return min
}

func main() {
	sc := NewScanner(os.Stdin)
	for {
		flg, in := sc.nextLine()
		if flg {
			break
		}
		if !check(in) {
			fmt.Println(-1)
			continue
		}
		fmt.Println(cww(in))
	}
}