Please read the following table in Markdown format and then answer the question according to the table. Table cells in one row are seperated by '|', and different rows are seperated by '
'.

Table:
| Prefix size | Network mask | Available subnets | Usable hosts per subnet | Total usable hosts |
| --- | --- | --- | --- | --- |
| /24 | 255.255.255.0 | 1.0 | 254.0 | 254.0 |
| /25 | 255.255.255.128 | 2.0 | 126.0 | 252.0 |
| /26 | 255.255.255.192 | 4.0 | 62.0 | 248.0 |
| /27 | 255.255.255.224 | 8.0 | 30.0 | 240.0 |
| /28 | 255.255.255.240 | 16.0 | 14.0 | 224.0 |
| /29 | 255.255.255.248 | 32.0 | 6.0 | 192.0 |
| /30 | 255.255.255.252 | 64.0 | 2.0 | 128.0 |
Question:
When the network mask is 255.255.255.252 what is the prefix size?
Answer:
/30