In the city of Seoul, a river called the Han River flows in the east-west direction. On the northern shore of the river there are
One key condition is that the number of boats sent by the school numbered
Task
Given
Input Specification
The first line of the input contains a single integer
Output Specification
The output should consist of a single line with the remainder when the number of all possible cases the schools may send boats to the festival is divided by
Sample Input
2
1 2
2 3
Sample Output
7
Explanation for Sample Output
There are
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