For 2 4 it should be days 2 and 4.
For 100 200 it shoould be 100, 102...148(count must be 25 already)...200(count is 51).

Janus brokes fuses every ODD day. There is 1 odd day in interval [2..4]

Hmm... I see that I just did not understand the task clearly. For me it was like day 2 is the first day, but it is just the starting point of counting... Thanks.