Problem C. Spring Outing

    单点时限:1000ms

    内存限制:256MB

    You class are planning for a spring outing. N people are voting for a
    destination out of K candidate places.

    The voting progress is below:

    First the class vote for the first candidate place. If more than half of the
    class agreed on the place, the place is selected. The voting ends.

    Otherwise they vote for the third candidate place in the same way and go on.

    If no place is selected at last there will be no spring outing and everybody
    stays at home.

    Before the voting, the Chief Entertainment Officer did a survey, found out
    every one’s preference which can be represented as a permutation of 0, 1, …
    K. (0 is for staying at home.) For example, when K=3, preference “1, 0, 2, 3”
    means that the first place is his first choice, staying at home is the second
    choice, the second place is the third choice and the third place is the last
    choice.

    The Chief Entertainment Officer sends the survey results to the class. So
    everybody knows the others’ preferences. Everybody wants his more prefered
    place to be selected. And they are very smart, they always choose the optimal
    strategy in the voting progress to achieve his goal.

    Can you predict which place will be selected?

    The next N lines each contain a permutation of 0~K, representing someone’s
    preference.

    For 40% of the data, 1 <= N, K <= 10

    For 100% of the data, 1 <= N, K <= 1000

    Output the selected place. Or “otaku” without quotes if no place is selected.

    In the sample case, if the second peoson vote against the first place, no
    place would be selected finally because the first person must vote against the
    second place for his own interest. Considering staying at home is a worse
    choice than the first place, the second person’s optimal strategy is voting
    for the first place. So the first place will be selected.

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