You are given a positive integer . Calculate the lower median of the numbers .
The lower median of a sequence of numbers is the number at position when the sequence is sorted. For example, the lower median of the sequence is and the lower median of the sequence is .
Input Specification
The first and only line of input contains the integer .
Constraints
Subtask 1 [10%]
Subtask 2 [20%]
Subtask 3 [20%]
Subtask 4 [25%]
Subtask 5 [25%]
Output Specification
Output one number: the lower median in the problem statement.
Sample Input 1
7
Sample Output 1
1
Explanation for Sample Output 1
The sequence is equal to . When sorted, this becomes . The lower median is the element of this sorted sequence, which is .
Sample Input 2
50
Sample Output 2
6
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