def ReadFile():
    for P in open("data4.txt","r").read().split("\n"):
        yield P
Next = ReadFile().next

def WriteLine(Line):
    open("out4.txt","a").write(str(Line) + "\n")

for QQ in xrange(5):
    Needed = int(Next())
    N  = int(Next())
    
    Coins = set(int(Next()) for i in xrange(N))
    
    Mins = [99999999]*(Needed+1)
    Mins[0] = 0

    for V in xrange(1,Needed+1):
        for Coin in Coins:
            if Coin<=V:
                Mins[V] = min(Mins[V],Mins[V-Coin] + 1)

    WriteLine(Mins[Needed])