#include <algorithm>
#include <cstdio>

using namespace std;

const int N=1000005;

int a[N];

int main()
{
    freopen("zombie.in", "r", stdin);
    freopen("zombie.out", "w", stdout);
    int n, d, k, i, j, sol=0;
    scanf("%d%d%d", &d, &n, &k);
    for(i=1;i<=n;i++)
    {
        scanf("%d", &a[i]);
    }
    sort(a+1, a+n+1);
    a[n+1]=N*1000;
    for(i=2, j=1;i<=n+1;i++)
    {
        if(a[i]-a[j]>=d)
        {
            sol+=min(i-j, k);
            j=i;
        }
    }
    printf("%d", sol);
}