题目描述

After having drifted about in a small boat for a couple of days, Akira Crusoe Maeda was finally cast ashore on a foggy island. Though he was exhausted and despaired, he was still fortunate to remember a legend of the foggy island, which he had heard from patriarchs in his childhood. This must be the island in the legend. In the legend, two tribes have inhabited the island, one is divine and the other is devilish, once members of the divine tribe bless you, your future is bright and promising, and your soul will eventually go to Heaven, in contrast, once members of the devilish tribe curse you, your future is bleak and hopeless, and your soul will eventually fall down to Hell.

In order to prevent the worst-case scenario, Akira should distinguish the devilish from the divine. But how? They looked exactly alike and he could not distinguish one from the other solely by their appearances. He still had his last hope, however. The members of the divine tribe are truth-tellers, that is, they always tell the truth and those of the devilish tribe are liars, that is, they always tell a lie.

He asked some of them whether or not some are divine. They knew one another very much and always responded to him "faithfully" according to their individual natures (i.e., they always tell the truth or always a lie). He did not dare to ask any other forms of questions, since the legend says that a devilish member would curse a person forever when he did not like the question. He had another piece of useful informationf the legend tells the populations of both tribes. These numbers in the legend are trustworthy since everyone living on this island is immortal and none have ever been born at least these millennia.

You are a good computer programmer and so requested to help Akira by writing a program that classifies the inhabitants according to their answers to his inquiries.

输入格式

The input consists of multiple data sets, each in the following format :

n p1 p2
xl yl a1
x2 y2 a2
...
xi yi ai
...
xn yn an

The first line has three non-negative integers n, p1, and p2. n is the number of questions Akira asked. pl and p2 are the populations of the divine and devilish tribes, respectively, in the legend. Each of the following n lines has two integers xi, yi and one word ai. xi and yi are the identification numbers of inhabitants, each of which is between 1 and p1 + p2, inclusive. ai is either yes, if the inhabitant xi said that the inhabitant yi was a member of the divine tribe, or no, otherwise. Note that xi and yi can be the same number since "are you a member of the divine tribe?" is a valid question. Note also that two lines may have the same x's and y's since Akira was very upset and might have asked the same question to the same one more than once.

You may assume that n is less than 1000 and that p1 and p2 are less than 300. A line with three zeros, i.e., 0 0 0, represents the end of the input. You can assume that each data set is consistent and no contradictory answers are included.

输出格式

For each data set, if it includes sufficient information to classify all the inhabitants, print the identification numbers of all the divine ones in ascending order, one in a line. In addition, following the output numbers, print end in a line. Otherwise, i.e., if a given data set does not include sufficient information to identify all the divine members, print no in a line.

题目大意

题目描述

在小船上漂流了几天后，Akira Crusoe Maeda 终于被抛到了一个雾蒙蒙的岛上。尽管他疲惫不堪，绝望不已，但他仍然幸运地记得他童年时从族长那里听到的雾岛传说。这一定是传说中的岛屿。传说中有两个部落居住在岛上，一个是神圣的，另一个是邪恶的，一旦神圣部落的成员保佑你，你的未来就会光明有希望，你的灵魂最终会去天堂，相比之下，一旦邪恶部落的成员诅咒你，你们的未来就会黯淡无望，你的心灵最终会坠入地狱。

为了防止最坏的情况发生，Akira Crusoe Maeda 应该区分恶魔和神灵。但是怎么做？他们看起来完全一样，他无法仅凭外表区分他们。然而，他还有最后的希望。神圣部落的成员是说实话的人，也就是说，他们总是说实话，而邪恶部落的成员则是骗子，也就是他们总是撒谎。

他问他们中的一些人是否有些是神圣的。他们彼此非常了解，总是根据自己的个性“忠实地”回应他（即，他们总是说实话或撒谎）。他不敢问任何其他形式的问题，因为传说中，当一个恶魔成员不喜欢这个问题时，他会永远诅咒一个人。他有另一条有用的信息，传说告诉了两个部落的人口。传说中的这些数字是值得信赖的，因为生活在这个岛上的每个人都是不朽的，至少在这几千年里没有人出生过。

你是一名优秀的计算机程序员，因此被要求帮助 Akira 编写一个程序，根据居民对他的询问的回答对他们进行分类。

输入格式

输入由多行组成，每个测试点的格式如下：

n p1 p2
xl yl a1
x2 y2 a2
...
xi yi ai
...
xn yn an

第一行有三个非负整数 $n$、$p_1$ 和 $p_2$。$n$ 是 Akira 提出的问题数量。$p_l$ 和 $p_2$ 分别是传说中神圣部落和恶魔部落的人口。接下来的 $n$ 行中的每一行都有两个整数 $x_i$、$y_i$ 和一个单词 $a_i$。$x_i$ 和 $y_i$ 是居民的识别号，每个识别号在 $1$ 和 $p_1+p_2$（包括 $1$ 和 $p_1+p_2$ ）之间。$a_i$ 要么是肯定的，要么是否定的。请注意，$x_i$ 和 $y_i$ 可以是同一个数字，因为“你是神族的成员吗？”是一个有效的问题。还要注意，两行可能有相同的 $x$ 和 $y$ ，因为 Akira 非常沮丧，可能不止一次向同一行问同一个问题。

你可以假设 $n$ 小于 $1000$，$p_1$ 和 $p_2$ 小于 $300$。如果一行有三个零，即 0 0 0，表示输入的结束。你可以假设每个测试点都是一致的，没有矛盾的答案。

输出格式

对于每个数据集，如果它包含足够的信息来对所有居民进行分类，请按升序输出所有神圣居民的识别号，一行一个。此外，在输出数字之后，打印 end 于最后一行。否则，即如果给定的数据集不包括足够的信息来识别所有神圣的成员，请在最后一行中打印 no。

说明/提示

对于 $100\%$ 的数据，每个数据点内最多 10 组数据，$n<1000$，$p_1,p_2<300$，$1\le x_i, y_i \le p_1+p_2$。

2 1 1
1 2 no
2 1 no
3 2 1
1 1 yes
2 2 yes
3 3 yes
2 2 1
1 2 yes
2 3 no
5 4 3
1 2 yes
1 3 no
4 5 yes
5 6 yes
6 7 no
0 0 0

no
no
1
2
end
3
4
5
6
end