Python - How to differentiate SMOTE resampling from original data

I over sampled my data using SMOTE like so:

>>> from imblearn.over_sampling import SMOTE
>>> X_resampled, y_resampled = SMOTE().fit_resample(X, y)

So now X_resampled, y_resampled are larger than the original data set. How can I tell apart the original data from the synthetic samples?