#include <bits/stdc++.h>
using namespace std;
int n, i, i1, i2, k, d, n1, nr = 0;
int t[1000005];
int main(){
    freopen("zombie.in", "r", stdin);
    freopen("zombie.out", "w", stdout);
    scanf("%d%d%d", &d, &n, &k);
    for (i = 1; i <= n; i ++)
        scanf("%d", &t[i]);
    i2 = 1;
    i1 = 1;
    while(i1<=n && i2<=n){
    n1 = 1;
    i1 = i2;
    i2++;
    while(i2 <= n && t[i2]-t[i1] <=d){
    	i2++;
    	n1++;
	}
	if (n1 > k) nr+=k;
	 else nr+=n1;
 	}
    printf("%d\n", nr);
    return 0;
}