There are more games?? How ridiculous!
In front of you lies a glass bridge with () panels. These panels are designed to hold piles of cookies, of course.
Initially, there is one cookie on panel . The Front Man proceeds to apply the following operation to the panels, sequentially, with from to :
For each cookie on panel , add a cookie to panels , , and .
The Front Man then asks you a simple question: How many cookies are on panel ?
Input Specification
The first line contains the integer ().
Output Specification
Output one line containg the number of cookies on panel .
Subtasks
Subtask 1 [20%]
Subtask 2 [80%]
No additional constraints.
Sample Input 1
3
Sample Output 1
2
Sample Explanation 1
The number of cookies on the panels are [].
When applying the operation to panel , one cookie is added to each of panels , , and .
When applying the operation to panel , one cookie is added to each of panels , , and . This has no effect on panel .
When applying the operation to panel , two cookies are added to each of panels , , and . This has no effect on panel .
Therefore, the number of cookies on panel is after all the operations have been applied.
Sample Input 2
999999999999999999
Sample Output 2
6893394
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