C++ :

#define MAXN 500010UL
#define MAXL 100010UL

#include <cstdio>
#include <queue>
#include <deque>

std::deque<int> q[MAXL];

struct Point{
	int id,d;
	friend bool operator < (Point a,Point b){
		return a.d<b.d;
	}
};

std::priority_queue<Point> que;
int n,k,p,lis[MAXN],Ans,rs;
bool ex[MAXL];


int main(){
	scanf("%d%d%d",&n,&k,&p);
	for(int i=1;i<=p;i++) scanf("%d",&lis[i]),q[lis[i]].push_back(i);
	for(int i=1;i<=n;i++) q[i].push_back(0x2ffffff);
	for(int i=1,a;i<=p;i++){
		a=lis[i];
		if(!ex[a]){
			Ans++;
			if(rs==k){
				while(!ex[que.top().id]) que.pop();
				ex[que.top().id]=false;rs--;que.pop();
			}
			rs++;
		}
		q[a].pop_front();
		Point temp;ex[a]=true;
		temp.id=a;
		temp.d=q[a].front();
		que.push(temp);
	}
	printf("%d",Ans);
	return 0;
}