require"prime"
m,n,*c=$<.read.split.map &:to_i
s=m/c[-1]
a=[]
f=->x{a[x]||=c.map{|e|x==e ?1:(x>e&&0<t=f[x-e])?t+1:0}.max}
Prime.each(m).reverse_each{|p|s+=f[m-p]}
p s