#include <iostream>
#include <fstream>
using namespace std;
int v[1000005];
int main()
{
    ifstream cin("zombie.in");
    ofstream cout("zombie.out");
    int n,d,k,i,s=0;
    cin>>d>>n>>k;
    for(i=1;i<=n;i++){
        cin>>v[i];
    }
    for(i=1;i<=n;i++){
        int cnt=0;
        int cop=i;
        while(v[i]-v[cop]<d && i<=n){
            cnt++;
            i++;
        }
        if(cnt>=k)
           s+=k;
        else
           s+=cnt;
        if(i<n)
        i--;
        else
        break;
    }
    cout<<s;
    return 0;
}