from math import inf


def main():
    S = input()
    minimum = inf

    for idx, letter in enumerate(S):
        if letter != "c":
            continue
        first_w_idx = S.find("w", idx)
        if first_w_idx == -1:
            break

        second_w_idx = S.find("w", first_w_idx+1)
        if second_w_idx == -1:
            break

        minimum = min(minimum, second_w_idx-idx+1)
    if minimum == inf:
        print(-1)
    else:
        print(minimum)


if __name__ == "__main__":
    main()