require'prime'
m,n,*c=$<.read.split.map &:to_i
d=[-1]*m<<0
m.downto(1){|i|c.map{|j|d[i-j]=d[i]+1 if j<=i&&d[i-j]<d[i]}}
p d.max+(0..m).inject{|p,c|p+(c.prime?&&d[c]>0?d[c]:0)}