def f(lt,s,e,t,mx): 
    flag=False
    while s!=e:
        if t==lt[s]:
            flag=True
            break
        s=(s+1)%mx
    return flag

m,n = map(int,input( ).split( ))   
la = list(map(int,input( ).split( )))   
maxsize=m+1
lb=[-1]*maxsize
head,tail=0,0
ans=0
for i in range(n):
    t=la[i]
    if not f(lb,head,tail,t,maxsize):
        if (tail+1)%maxsize==head:
            head=(head+1)%maxsize
        lb[tail]=t
        tail=(tail+1)%maxsize
        ans+=1
print(ans)