#include <iostream>
#include <fstream>
using namespace std;
ifstream in("zombie.in");
ofstream out("zombie.out");
long long d, n, k, t, pr, l, z, cost;
int main(){
    in>>d>>n>>k;
    in>>pr;
    l=pr;
    z++;
    for(int i=1; i<n; i++){
        in>>t;
        if(t<pr+d){
            z++;
        }else{
            cost+=min(z, k);
            z=1;
            pr=t;
        }
    }
    if(z>0)cost+=min(z, k);
    out<<cost;
    return 0;
}