Why does my compiler say invalid syntax then highlight...?

[Nathan Pinno]

Why does my compiler say invalid syntax and then highlight the
quotation marks in the following code:

# This program is to find primes.
primes = []
import math
import gmpy
while 1:
    run = int(raw_input("Do you want to calculate primes? 1 = yes and
2 = no. "))
    if run == 1:
        y = int(raw_input("What number do you want to use as the final
number to calculate with? "))
        x = int(raw_input("What number do you want to start
calculating primes from? "))
        while x < 2:
            print "Number must be at least 2 for math reasons."
        else:
            while x < y:
                prime = math.cos(gmpy.pi(0) * gmpy.fac((x-1)) / x)
                if prime < 0:
                    primes.append(x)
                else:
                    print x " is not prime. " # highlights the final "
here
                x = x + 1
            print primes
    elif run == 2:
        break
    else:
        print "Sorry, not a choice. Please enter your choice again."
print "Goodbye."

How do I fix such an invalid syntax?

TIA,
Nathan Pinno