# Problem 540: Counting primitive Pythagorean triples
A Pythagorean triple consists of three positive integers \$a, b\$ and
\$c\$ satisfying \$a\^2+b\^2=c\^2\$. The triple is called primitive if
\$a, b\$ and \$c\$ are relatively prime. Let P(\$n\$) be the number of
primitive Pythagorean triples with \$a < b < c <= n\$. For
example P(20) = 3, since there are three triples: (3,4,5), (5,12,13) and
(8,15,17). You are given that P(106) = 159139. Find P(3141592653589793).