// Function that returns true if n
// is prime else returns false
function isPrime(n)
{
    // Corner cases
    if (n <= 1) return false;
    if (n <= 3) return true;
     
    // This is checked so that we can skip
    // middle five numbers in below loop
    if (n%2 == 0 || n%3 == 0) return false;
     
    for (let i=5; i*i<=n; i=i+6)
        if (n%i == 0 || n%(i+2) == 0)
        return false;
     
    return true;
}