everyone has answered excellently using the date, let me try to answer it using pandas
dt = pd.to_datetime('2008/08/18', format='%Y/%m/%d')
dt1 = pd.to_datetime('2008/09/26', format='%Y/%m/%d')
(dt1-dt).days
This will give the answer. In case one of the input is dataframe column. simply use dt.days in place of days
(dt1-dt).dt.days