package main

import "fmt"

func main() {
	var s string
	fmt.Scan(&s)
	var c int
	w1 := len(s) + 1
	w2 := len(s) + 2
	ans := len(s) + 1
	for j := len(s) - 1; j >= 0; j-- {
		if s[j] == 'w' {
			w1, w2 = j, w1
		}
		if s[j] == 'c' {
			c = j
			if w2 < len(s) {
				ans = minInt(ans, w2-c+1)
			}
		}
	}
	if ans == len(s)+1 {
		ans = -1
	}
	fmt.Println(ans)
}

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