More than two years.
Please clarify your "more than two years" response. Were you living together for two years, living in the same city and seeing each other in person for two years, or did you make multiple trips to be together, in person, for a total of two years? Based on the evidence you sent (photos, online chats, tickets), it seems more like a virtual relationship with one or more brief visits in person. If you were in fact together in person for more than two years, you should have stronger evidence such as an apartment lease or other documentation like utility bills together. For a K-1, in most countries, evidence of at least one in person meeting within the last two years is sufficient, but for Egypt they seem to be wanting more, maybe because of high fraud by others. Is this an arranged marriage, and what were the circumstances of your meeting? I agree with others, you should be fine with more evidence at the interview. Good luck!