# This program simulates flipping a coin 1000 times and
# counts the number of flips which come out heads. How far
# away from the expected number of 500 is the actual result?
# Try running this program a bunch of times in order to see
# the distribution.

import random

def makestr(n):
    return [random.randint(0,1) for _ in xrange(n)]

def numheads(s):
    count = 0
    for i in range(len(s)):
        if s[i] == 1:
            count += 1
    return count

s = makestr(1000)
print numheads(s)