fn main() {
    let mut s = String::new();
    std::io::stdin().read_line(&mut s).ok();
    let s = s.trim();

    let mut counts = vec![];
    let mut n = 0;
    for c in s.chars() {
        if c == 'w' {
            n += 1;
        }
        counts.push(n);
    }

    let mut min: Option<usize> = None;
    for (i, c) in s.chars().enumerate() {
        if c == 'c' {
            if let Some(j) = counts.iter().position(|&n| n == counts[i] + 2) {
                min = min.map_or(Some(j - i), |n| Some(n.min(j - i)));
            }
        }
    }

    min.map_or_else(|| println!("-1"), |n| println!("{}", n + 1));
}