x, y = 1, 2

def f():
    x, y = 3, 4
    print "f(): x=%d, y=%d" % (x, y)
    z = 5

def g():
    x = 6
    f()
    print "g(): x=%d, y=%d" % (x, y)

y = 7
f()
print "__main__: x=%d, y=%d" % (x, y)

x = 8
g()
print "g(): x=%d, y=%d" % (x, y)