Two-Sided Skyline Tour
Along a west-to-east trail stand observation towers. Their distinct heights are .
A tour is formed by choosing a nonempty subsequence of towers. More precisely, a tour chooses indices
The chosen tower at index is a west-record if it is taller than every tower chosen before it. That is, for every . The first chosen tower is always a west-record.
The chosen tower at index is an east-record if it is taller than every tower chosen after it. That is, for every . The last chosen tower is always an east-record.
A chosen tower may be both a west-record and an east-record. Two tours are distinct if their chosen index sequences are different.
Count the tours containing exactly west-records and exactly east-records. Since the answer can be large, report it modulo .
Input
The first line contains three integers , , and , where is the number of towers, is the required number of west-records, and is the required number of east-records.
Output
Print one integer: the number of tours having exactly west-records and exactly east-records, modulo .
Samples
Sample 1
Input
4 2 1 2 4 1 3
Output
4
The valid tours have index sequences , , , and .