def main():
    s = list(input())
    min_length = float("inf")
    c_index = -1
    first_w_index = -1
    for i in range(len(s)):
        if s[i] == "c":
            c_index = i
        elif s[i] == "w":
            if c_index != -1 and first_w_index == -1:
                first_w_index = i
            elif first_w_index != -1:
                current_length = i - c_index + 1
                if current_length < min_length:
                    min_length = current_length

                first_w_index = i
    if min_length == float("inf"):
        print(-1)
    else:
        print(min_length)



if __name__ == "__main__":
    main()