given an array consists of $$$n$$$ integers and an integer $$$p$$$, find number of pair($$$i,j$$$):

so that $$$i \lt j$$$ and $$$(a[i]*a[j])$$$ $$$mod$$$ $$$p$$$ $$$=$$$ $$$(a[i]+a[j])$$$ $$$mod$$$ $$$p$$$

$$$n \lt =10^5$$$

$$$1 \lt p \lt =10^9$$$