#define int long long
#define elif else if
#define fin(x) freopen (x, "r", stdin)
#define fout(x) freopen (x, "w", stdout)
#define reg(i,x,y) for (register int i = (x); i <= (y); ++i)
#define Reg(i,x,y) for (register int i = (y); i >= (x); --i)
using namespace std;
int m,n,s = 0;
vector<int> a;
map<int,bool> ma;
queue<int> q;
inline int read (void) {int x = 0,f = 0;char ch = getchar ();while (!isdigit (ch)) {f |= (ch == '-');ch = getchar ();}while (isdigit (ch)) x = (x << 1) + (x << 3) + (ch ^ 48),ch = getchar ();return f ? -x : x;}
inline string rstr (void) {string s = "";char ch = getchar ();while (ch != '\n' && ch != EOF) {if (ch != ' ') s += ch;ch = getchar ();}return s;}
inline char rch (void) {char ch = getchar ();while (ch == ' ' || ch == '\n') ch = getchar ();return ch;}
inline void write (int x = 0) {if (x < 0) putchar ('-'),x = -x;if (x > 9) write (x / 10);putchar (x % 10 | 48);}
inline void write_ (int x = 0,char ch = ' ') {write (x);putchar (ch);}
signed main ()
{
	m = read (),n = read ();
	a.push_back (0);
	reg (i,1,n) a.push_back (read ());
	int p = 0;
	reg (i,1,n)
		if (!ma[a[i]])
		{
			if (s < m) ++s,ma[a[i]] = true,++p,q.push (a[i]);
				else ma[a[i]] = true,ma[q.front ()] = false,q.pop (),++p,q.push (a[i]);
		}
	write (p);
	return 0;
}

#include <bits/stdc++.h>
using namespace std;
int a[1100],b[1100],k,m,n,t;
int main() {
    cin>>m>>n;
    for (int i=1;i<=n;i++) {
        cin>>t;
        if (b[t]==1) continue;
        a[++k]=t;
        b[t]=1;
        if (k>m) b[a[k-m]]=0;
    }
    cout<<k;
    return 0;
}