Vitya in the Countryside

题目描述 我们知道每个月月亮从月牙到圆形切换，zpy把月亮的圆的程度定义了0~15级，那么一个月30天月亮圆的程度变化为：0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 14, 13, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1。每个月都是这样周期的从0变到15再变到1。 zpy将最近n天月亮的变化记录下来，现在问你，下一天月亮是变大还是变小，变大输出“UP”，变小输出”DOWN”。 输入 第一行输入n 第二行输入n个整数(0到15之间的整数)，代表最近n天月亮变化情况 输出 下一天月亮变大输出“UP”，变小输出”DOWN”。 如果不能确定变大还是变小就输出”-1”。 样例输入 5 3 4 5 6 7 样例输出 UP 提示 样例输入2： 7 12 13 14 15 14 13 12 样例输出2： DOWN 样例输入3： 1 8 样例输出3： -1 【数据规模和约定】 1<=n<=100

Every summer Vitya comes to visit his grandmother in the countryside. This summer, he got a huge wart. Every grandma knows that one should treat warts when the moon goes down. Thus, Vitya has to catch the moment when the moon is down. Moon cycle lasts 30 days. The size of the visible part of the moon (in Vitya's units) for each day is $ 0 $ , $ 1 $ , $ 2 $ , $ 3 $ , $ 4 $ , $ 5 $ , $ 6 $ , $ 7 $ , $ 8 $ , $ 9 $ , $ 10 $ , $ 11 $ , $ 12 $ , $ 13 $ , $ 14 $ , $ 15 $ , $ 14 $ , $ 13 $ , $ 12 $ , $ 11 $ , $ 10 $ , $ 9 $ , $ 8 $ , $ 7 $ , $ 6 $ , $ 5 $ , $ 4 $ , $ 3 $ , $ 2 $ , $ 1 $ , and then cycle repeats, thus after the second $ 1 $ again goes $ 0 $ . As there is no internet in the countryside, Vitya has been watching the moon for $ n $ consecutive days and for each of these days he wrote down the size of the visible part of the moon. Help him find out whether the moon will be up or down next day, or this cannot be determined by the data he has.

The first line of the input contains a single integer $ n $ ( $ 1<=n<=92 $ ) — the number of consecutive days Vitya was watching the size of the visible part of the moon. The second line contains $ n $ integers $ a_{i} $ ( $ 0<=a_{i}<=15 $ ) — Vitya's records. It's guaranteed that the input data is consistent.

If Vitya can be sure that the size of visible part of the moon on day $ n+1 $ will be less than the size of the visible part on day $ n $ , then print "DOWN" at the only line of the output. If he might be sure that the size of the visible part will increase, then print "UP". If it's impossible to determine what exactly will happen with the moon, print -1.

5
3 4 5 6 7

UP

7
12 13 14 15 14 13 12

DOWN

1
8

-1

In the first sample, the size of the moon on the next day will be equal to $ 8 $ , thus the answer is "UP". In the second sample, the size of the moon on the next day will be $ 11 $ , thus the answer is "DOWN". In the third sample, there is no way to determine whether the size of the moon on the next day will be $ 7 $ or $ 9 $ , thus the answer is -1.