For some time now, there have been several businesses dedicated to the sale of extraterrestrial real estate on the planet Mars. The problem is that, as there is no centralised database, the same property may have been sold twice, or several properties, owned by different people, may intersect each other. Every property has a rectangular shape and one of its sides runs alongside one of the major Martian roads. Moreover, the length of the sides that are perpendicular to the road are fixed for every road. Mars roads are straight lines. So, a property may be identified by the name and the side of the road, and the coordinates of the two corners next to the road. Two properties intersect if the corresponding rectangles intersect and the intersection area is positive. Write a program that, given a sequence of properties on the same side of a road, determines whether at least two of them intersect. Input The first line contains an integer T (1 ≤ T ≤ 32), which is the number of test cases. The following lines contain T test cases. The first line of a test case contains an integer N (1 ≤ N ≤ 50000), which is the length of the sequence of properties. Each of the following N lines contains four non-negative integers, X1, Y1, X2 and Y2, separated by a space. These integers do not exceed 231 − 1. The pairs (X1,Y1) and (X2,Y2) specify the x-coordinate and the y-coordinate of the two property corners next to the road. Output The output consists of T lines. The i-th line contains the message: • ‘No problem’, if no two distinct elements of the i-th sequence of properties intersect; or • ‘Difficult problem(s)’, otherwise. Sample Input 3 4 100 214 120 254 55 124 20 54 12045 24104 12046 24106 56 126 100 214 5 4141 4196 4123 4196 761 4196 759 4196 757 4196 760 4196 0 4196 2 4196 144 4196 145 4196 4 60 30 22 11
2/2 214 107 256 128 48 24 46 23 214 107 256 128 Sample Output No problem Difficult problem(s) Difficult problem(s)