#include <cstdio>
#include <cstdlib>
#include <cmath>
using namespace std;


#define nmax 2000010

int v[nmax], N, K, D, sol, crt;


int main()
{
    freopen("zombie.in", "r", stdin);
    freopen("zombie.out", "w", stdout);
    int i;
    scanf("%i %i %i", &D, &N, &K);
    for(i = 1; i <= N; i++) scanf("%i", &v[i]);
    for(i = 1; i <= N; )
    {
          if(v[i + K] - v[i] > D) i ++, sol ++;
          else
          {
              crt = i;
              for(;v[i + K] - v[crt] <= D && i <= N; i++);
              sol += K;
          }
    }
    printf("%i\n", sol);
    return 0;
}