Perfect squares

Write a function IsSquare(k) that returns true if a non-negative integer $k$ is the square of an integer and false otherwise. Using it, count how many of the $n$ given numbers are perfect squares. $0 = 0^2$ is a perfect square too.

The first line contains $n$ ($1 \le n \le 1000$). The second line contains $n$ integers ($0 \le a_i \le 10^{18}$).

A single integer — the number of perfect squares.

Do not compare the root as a floating-point number: sqrt(x) == floor(sqrt(x)) is wrong around $10^{18}$ — in a double the root of $999999999^2 - 1$ comes out as exactly $999999999$, so the number looks like a square. Convert the root to an integer and check : (in Python — ).