def main():
    line = input()
    chars = list(line)
    find_c = False
    find_w1 = False
    for i in range(len(chars)):
        if chars[i] == 'c':
            find_c = True
            c_index = i
        if chars[i] == 'w':
            if find_w1:
                print(i - c_index + 1)
                return
            else:
                find_w1 = True
    print(-1)


if __name__ == '__main__':
    main()