a=$<.map &:to_i
t=a[0]
n=a[1]
d=[0]
(1..1<<n).map{|h|d<<(0...n).map{|i|h[i]>0?(x=d[h^1<<i];y=t-x%t;y<(b=a[2+i])?x+b+y:x+b):1e9}.min}
p (d[-2]+t-1)/t