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  • Andrew Ngunjiri thinks this is interesting:

Let’s configure this task. The following prefix denies any prefix as long as the prefix length is greater than or equal to 8 and less than or equal to 26:

From

Cover of CCIE Routing and Switching v5.1 Foundations: Bridging the Gap Between CCNP and CCIE

Note

ip prefix-list DEFAULT seq 7 deny 0.0.0.0/0 le 26 should be able to work. Only requirement is get /26 or less.