#include <bits/stdc++.h>
#define ll long long
using namespace std;
ifstream fin("zombie.in");
ofstream fout("zombie.out");
int d,n,k,i,j;
int a[1000001];
ll sol;
int main()
{
    fin>>d>>n>>k;
    for(i=1;i<=n;i++)fin>>a[i];
    for(i=1;i<=n;)
    {
        j=i;
        while(a[j]-a[i]<=d && j<=n)j++;
        sol+=min(j-i,k);
        i=j;
    }
    fout<<sol<<"\n";
    return 0;
}