Why do I get different formats of timestamps on converting these two strings to Timestamp type in Python? 

```
pd.to_datetime('05/09/2017 17:10')
>>>>Timestamp('2017-05-09 17:10:00')

pd.to_datetime('29/09/2017 17:10')
>>>>Timestamp('2017-09-29 17:10:00')

```

I have also tried 

```
 pd.to_datetime('29/09/2017 17:10', format = "%d%m%Y")

```

to which I get 

```
ValueError: time data '29/09/2017 17:10' does not match format '%d%m%Y' (match)

```

I would like to get my timestamps in Timestamp('2017-05-09 17:10:00') format.