package main

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

const MaxInt = math.MaxInt64

var scanner *bufio.Scanner

func nextChar(s string, c byte, currPos int) int {
	currPos++
	for currPos < len(s) {
		if s[currPos] == c {
			return currPos
		}
		currPos++
	}
	return -1
}

const (
	c_ch = 'c'
	w_ch = 'w'
)

func main() {
	var s string
	fmt.Scanln(&s)
	c := nextChar(s, c_ch, -1)
	w1 := nextChar(s, w_ch, -1)
	w2 := nextChar(s, w_ch, w1)
	if (c == -1) || (w1 == -1) || (w2 == -1) {
		fmt.Println(-1)
		return
	}
	min := len(s) + 1
	for (c != -1) && (w2 != -1) {
		if w1 < c {
			w1 = w2
			w2 = nextChar(s, w_ch, w2)
		} else {
			temp := w2 - c + 1
			if temp < min {
				min = temp
			}
			c = nextChar(s, c_ch, c)
		}
	}
	if min == len(s)+1 {
		min = -1
	}
	fmt.Println(min)
}

func init() {
	scanner = bufio.NewScanner(os.Stdin)
	scanner.Buffer([]byte{}, MaxInt)
	scanner.Split(bufio.ScanWords)
}

func Int() int {
	scanner.Scan()
	ret, _ := strconv.ParseInt(scanner.Text(), 10, 0)
	return int(ret)
}

func Ints(n int) []int {
	ret := make([]int, n)
	for i := 0; i < n; i++ {
		ret[i] = Int()
	}
	return ret
}

func Max(a, b int) int {
	if a < b {
		return b
	}
	return a
}

func Min(a, b int) int {
	if a < b {
		return a
	}
	return b
}