I'm sorry, but there really is no way to tell. It is not a matter of how many times you had sex. Both guys would have had live sperm in your body from October 26 through 31, and if you have regular cycles with periods that come every 28 days or so, it would be in that time period you got pregnant.
There will be no way to tell without doing a DNA test, and you should do it with both men to be sure there is no mistake.