#include <cstdio>
#include <algorithm>

using namespace std;

int v[1000005];

int main()
{
    freopen("zombie.in","r",stdin);
    freopen("zombie.out","w",stdout);
    int n , d , k , cost = 0;
    scanf("%d%d%d",&d,&n,&k);
    for(int i = 1 ; i <= n ; i++)
        scanf("%d",&v[i]);
    int st=1,dr;
    while(st <= n)
    {
        dr = st+1;
        while(dr <= n && d > v[dr]-v[st])
            dr++;
        cost += min(dr-st,k);
        st = dr;
    }
    printf("%d",cost);
    return 0;
}