def solve(num_str):
MAX, MIN = 65535, -65536
num_str_len = len(num_str)
i = 0
while num_str[i] == ' ':
i += 1
if i == num_str_len:
return 0
is_neg = True if num_str[i] == '-' else False
i += 1
ans = 0
is_valid = True
while i < num_str_len:
if num_str[i] < '0' or num_str[i] > '9':
print 'err'
is_valid = False
break
if not is_neg and ans > (MAX - (int(num_str[i]) - int('0'))) / 10:
return MAX
if is_neg and ans > (-MIN - (int(num_str[i]) - int('0'))) / 10:
return MIN
ans = ans * 10 + int(num_str[i]) - int('0')
i += 1
if is_valid:
return ans if not is_neg else -ans
return 0
print solve(' -65537fa')
