Algo- Given a sequence of memory access, give the minimum number of cache misses

Algo- Given a sequence of memory access, give the minimum number of cache
misses

Given inputs are: size of cache s, number of memory entries n, and a
series of memory accesses.
Give the minumum number of cache misses possible.
Example:
s = 3, n = 4 1 2 3 1 4 1 2 3 min_miss = 4
I've been stuck the entire day. Thanks in advance!