#include <cstdio>

long long n, k, d, a[1000001], first, sol, i;

int main()
{
    freopen("zombie.in", "r", stdin);
    freopen("zombie.out", "w", stdout);

    scanf("%lld %lld %lld", &d, &n, &k);
    for(i=1; i<=n; ++i) scanf("%lld", a+i);

    first=1;
    for(i=2; i<=n; ++i)
    {
        if(a[i]-a[first]<d) continue;
        else
        {
            if(i-first>=k)
            {
                first=i;
                sol+=k;
            }
            else
            {
                ++first;
                ++sol;
            }
        }
    }

    if(i-first>=k) sol+=k;
    else ++sol;

    printf("%lld\n", sol);

    return 0;
}