7983: ABC254 —— D - Together Square
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Description
You are given an integer N. Find the number of pairs (i,j) of positive integers at most N that satisfy the following condition:
- i×j is a square number.
Input
Input is given from Standard Input in the following format:
N
N
Output
Print the answer.
Constraints
$1≤N≤2×10^5$
$N$ is an integer.
$N$ is an integer.
Sample 1 Input
4
Sample 1 Output
6
The six pairs (1,1),(1,4),(2,2),(3,3),(4,1),(4,4) satisfy the condition.
On the other hand, (2,3) does not, since 2×3=6 is not a square number.
Sample 2 Input
254
Sample 2 Output
896