I am having issues with a port scanner I'm editing to use threads. This is the basics for the original code:

for i in range(0, 2000):  

    s = socket(AF_INET, SOCK_STREAM)  
    result = s.connect_ex((TargetIP, i))  

    if(result == 0) :  
        c = "Port %d: OPEN\n" % (i,)  

    s.close()

This takes approx 33 minutes to complete. So I thought I'd thread it to make it run a little faster. This is my first threading project so it's nothing too extreme, but I've ran the following code for about an hour and get no exceptions yet no output. Am I just doing the threading wrong or what?

import threading
from socket import *
import time

a = 0
b = 0
c = ""
d = ""

def ScanLow():
    global a
    global c

    for i in range(0, 1000):  
        s = socket(AF_INET, SOCK_STREAM)  
        result = s.connect_ex((TargetIP, i))  

        if(result == 0) :  
            c = "Port %d: OPEN\n" % (i,)  

        s.close()  
        a += 1

def ScanHigh():
    global b
    global d

    for i in range(1001, 2000):  
        s = socket(AF_INET, SOCK_STREAM)  
        result = s.connect_ex((TargetIP, i))  

        if(result == 0) :  
            d = "Port %d: OPEN\n" % (i,)  

        s.close()  
        b += 1

Target = raw_input("Enter Host To Scan:")
TargetIP = gethostbyname(Target)

print "Start Scan On Host ", TargetIP
Start = time.time()

threading.Thread(target = ScanLow).start()
threading.Thread(target = ScanHigh).start()

e = a + b

while e < 2000:
    f = raw_input()

End = time.time() - Start
print c
print d
print End

g = raw_input()