Max negative

print('Enter integer numbers, enter [.] to end sequence')
max_negative = -1000000
x = raw_input('-> ')
# if '.' or another symbol is inputed in the beginning
while x == '.' or x.isalpha() or x.isspace():
    x = raw_input('Enter number \n')
if int(x) < 0:
    max_negative = int(x)
while x != '.':
    x = raw_input('-> ')
    if not x.isdigit() and not x.isalpha() and not x.isspace():
        x = int(x)
        if x < 0 and x > max_negative:
            max_negative = x
print('Largest negative number is ' + str(max_negative))