#include <iostream>
#include <fstream>
#define MAX_N 1000000
using namespace std;
unsigned int v[MAX_N],n,k,d;

int main()
{
    long long int cakra=0,ct;
    bool ok=false;
    ifstream fin("zombie.in");
    fin>>d>>n>>k;
    for(int i=1;i<=n;++i)
    {
        ct=1;
        fin>>v[i];
        while((fin>>v[++i]),v[i]-v[i-1]<=d && i<=n)
        {
            ok=true;
            ct++;
        }
        if(i!=n)
            --i;
        if(!ok)
            ++cakra;
        else
            cakra+=((k>ct)?ct:k);
    }
    fin.close();
    ofstream fout("zombie.out");
    fout<<cakra;
    fout.close();
    return 0;
}