#include <fstream>
#include <algorithm>
#define int long long
using namespace std;

ifstream cin ("zombie.in");
ofstream cout ("zombie.out");

int v[1000005];

signed main() {
    int d,n,k;
    cin>>d>>n>>k;
    for (int i=1; i<=n; i++) {
        cin>>v[i];
    }
    sort(v+1,v+n+1);
    int sum=0,last=0,cnt=0,curr=0;
    for (int i=1; i<=n; i++) {
        int l=v[i]-last;
        if (curr+l<=d) {
            cnt++;
            curr+=l;
        }
        else {
            if (cnt>=k) sum+=k;
            else sum+=cnt;
            curr=0;
            cnt=0;
        }
        last=v[i];
    }
    if (cnt>=k) sum+=k;
    else sum+=cnt;
    cout<<sum;
}