<?php

/*
* Input/Output用のクラス
*/

namespace Coder;

class IO
{
    private $raw = [];
    private $count = 0;
    private $pointer = 0;

    /*
     * デリミタで区切った文字列を取得する
     * @param string
     * @return string
     */
    public function next($del = ' ') {
        if ($this->pointer >= $this->count) {
            $this->raw = explode("{$del}", trim(fgets(STDIN)));
            $this->count = count($this->raw);
            $this->pointer = 0;
        }
        $result = $this->raw[$this->pointer];
        $this->pointer++;
        return $result;
    }
    /*
     * 次にまだ文字列があるかを調べる
     * @return bool
     */
    public function hasNext() {
        return $this->pointer < $this->count;
    }
    /*
     * int型で文字列を取り出す
     * @return int
     */
    public function nextInt($del = ' ') {
        return (int)$this->next($del);
    }
    /*
     * double型で文字列を取り出す
     * @return double
     */
    public function nextDouble($del = ' ') {
        return (double)$this->next($del);
    }
    /*
     * 改行を末尾に追加して出力する
     * @param string
     */
    public static function out ($str = '') {
        echo $str . PHP_EOL;
    }
}

$io = new IO();

$str = $io->next();
$count_c = 0;
$count_w = 0;
$index = [];
$min = strlen($str);

for($i = 0; $i < strlen($str); $i++) {
    if ($str[$i] == 'c') {
        if ($count_c == 0) {
            $count_w = 0;
        }
        $count_c = 1;
        $index[] = $i;
    }
    if ($str[$i] == 'w') {
        $count_w++;
        if ($count_c == 1 && $count_w == 2) {
            foreach ($index as $v) {
                $tmp = $i - $v + 1;
                if ($min > $tmp && $tmp > 2) {
                    $min = $tmp;
                }
            }
            $io->out($min);
            exit;
        }
    }
}
$io->out('-1');