N 400 Question for Teacher 8 & P

Teacher 8 & Teacher P,

I'll file my N400, but I have a question on days outside U.S.

I studied 4.5 months in Germany via study abroad program of U.S. university.  During the 4.5 months study in Germany, I took my weekend time to visit other 10 Schengen countries and each time I spent 1 to 3 days (over 24 hours). Should I list all these countries I visited or just Germany? These small trips are all included in this study abroad Germany trip duration of 4.5 months.

I appreciate greatly if you can explain a little more in details.

Thanks a lot/Happy New Year