fn main() {
    let mut input = String::new();
    let _ = std::io::stdin().read_line(&mut input);

    let input = input.chars().collect::<Vec<char>>();
    let mut pos = 0;
    let mut check = vec![];
    let test = vec!['c', 'w', 'w'];
    let mut test_index = 0;

    for i in 0..input.len() {
        if test[test_index] == input[i] {
            check.push(i);
            test_index += 1;
            if check.len() == test.len() {
                break;
            }
        }
    }

    if check.len() == test.len() {
        println!("{}", check[check.len()-1] + 1 - check[0]);
    } else {
        println!("-1");
    }
}