Why the total number of observed otus does not agree with the total number of otus?

According to the artifacts made with the new version of qiime2, the total number of otus in my experiment is 108, but when I get the otus observed by the library and add them up, they are equal to 402, is this ok?
Could anyone explain why?

OTU Sample1 Sample2
1 123 456
2 0 5
3 42 69
Total OTUs: 3 OTUs in this sample: 2 OTUs in this sample: 3

If you add up OTUs in samples 1 and 2, you get 5, even though there are only 3 OTUs total.

This is because most OTUs are in multiple samples.