def main():
    line = input()
    #chars = list(line)
    count = line.count('w')
    if count < 2:
        print(-1)
        return
    else:
        c_index = line.find('c')
        if c_index == -1:
            print(-1)
            return
        first_w_index = line.find('w')
        next_w_index = line.find('w', first_w_index+1)
        c_all_index = get_c_all_index(line)
        tmp = -1
        for e in c_all_index:
            if e < first_w_index:
                tmp = e
        if tmp == -1:
            print(-1)
        else:
            print(next_w_index - tmp + 1)

def get_c_all_index(line):
    c_all_index = []
    for i in range(len(line)):
        if line[i] == 'c':
            c_all_index.append(i)
    return c_all_index


if __name__ == '__main__':
    main()