#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>>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;
}