{"raw_statement":[{"iden":"problem statement","content":"In CODE FESTIVAL XXXX, there are $N+1$ participants from all over the world, including Takahashi.\nTakahashi checked and found that the _time gap_ (defined below) between the local times in his city and the $i$\\-th person's city was $D_i$ hours. The time gap between two cities is defined as follows. For two cities A and B, if the local time in city B is $d$ o'clock at the moment when the local time in city A is $0$ o'clock, then the time gap between these two cities is defined to be $min(d,24-d)$ hours. Here, we are using $24$\\-hour notation. That is, the local time in the $i$\\-th person's city is either $d$ o'clock or $24-d$ o'clock at the moment when the local time in Takahashi's city is $0$ o'clock, for example.\nThen, for each pair of two people chosen from the $N+1$ people, he wrote out the time gap between their cities. Let the smallest time gap among them be $s$ hours.\nFind the maximum possible value of $s$."},{"iden":"constraints","content":"*   $1 \\leq N \\leq 50$\n*   $0 \\leq D_i \\leq 12$\n*   All input values are integers."},{"iden":"input","content":"Input is given from Standard Input in the following format:\n\n$N$\n$D_1$ $D_2$ $...$ $D_N$"},{"iden":"sample input 1","content":"3\n7 12 8"},{"iden":"sample output 1","content":"4\n\nFor example, consider the situation where it is $7$, $12$ and $16$ o'clock in each person's city at the moment when it is $0$ o'clock in Takahashi's city. In this case, the time gap between the second and third persons' cities is $4$ hours."},{"iden":"sample input 2","content":"2\n11 11"},{"iden":"sample output 2","content":"2"},{"iden":"sample input 3","content":"1\n0"},{"iden":"sample output 3","content":"0\n\nNote that Takahashi himself is also a participant."}],"translated_statement":null,"sample_group":[],"show_order":["default"],"formal_statement":null,"simple_statement":null,"has_page_source":true}