Problem with dichotomous comparison/test



Hello, I have a problem with comparison of two paired dichotomous samples (each sample 15 observations, each sample was measured after and before treatment-so I have four columns of "0" and "1");
Firstly, I used McNemar test and made test for paired group, for each of my samples, and now I don't know how to test two independent groups-normally, with ordinal scale, one would take differencies from each sample's columns before and after, and used U-mann whitney, but since this is 0-1 case I'm not sure what to do.
Can somebody help?