#include <cstdio>
#include <cstring>
#include <stack>
#include <vector>
#define X first
#define Y second
#define PB push_back
using namespace std;
const int N = 1e5 + 500;
const int OFF = (1 << 17);
typedef long long ll;
typedef pair < int, int > pii;
ll LO, HI = (ll)1e9, COST;
inline ll get_cost(pii &tmp){
return 100000LL * tmp.X + COST * tmp.Y;
}
inline pii bolji(pii A, pii B){
if(get_cost(A) < get_cost(B))
return A;
return B;
}
pii T[2 * OFF];
int prop[2 * OFF];
int n, d, tme[N], L;
vector < int > q[N];
void refresh(int x){
if(!prop[x]) return;
T[x].X += prop[x];
if(x < OFF){
prop[2 * x] += prop[x];
prop[2 * x + 1] += prop[x];
}
prop[x] = 0;
}
void update(int i, int a, int b, int lo, int hi){
refresh(i);
if(lo <= a && b <= hi) {
prop[i]++; refresh(i);
return;
}
if(a > hi || b < lo) { return; }
update(2 * i, a, (a + b) / 2, lo, hi);
update(2 * i + 1, (a + b) / 2 + 1, b, lo, hi);
T[i] = bolji(T[2 * i], T[2 * i + 1]);
}
void postavi(int i, int a, int b, int gdje, pii kog){
refresh(i); refresh(i ^ 1);
if(a == b){
T[i] = kog; return;
}
if(gdje <= (a + b) / 2)
postavi(2 * i, a, (a + b) / 2, gdje, kog);
else
postavi(2 * i + 1, (a + b) / 2 + 1, b, gdje, kog);
T[i] = bolji(T[2 * i], T[2 * i + 1]);
}
pii dp[N];
pii probaj(){
for(int i = 0;i < 2 * OFF;i++) T[i] = {N, N}, prop[i] = 0;
postavi(1, 0, OFF - 1, 0, {0, 0});
for(int i = 1;i <= n;i++){
for(int j : q[i]){
//printf("%d %d += 1\n", 0, j - 1);
update(1, 0, OFF - 1, 0, j - 1);
}
dp[i] = T[1]; dp[i].Y++; postavi(1, 0, OFF - 1, i, dp[i]);
// printf("dp[ %d ] = %d %d\n", i, dp[i].X, dp[i].Y);
}
return T[1];
}
int main(){
scanf("%d%d%d", &n, &d, &L);
stack < int > Q;
for(int i = 1;i <= n;i++){
scanf("%d", tme + i);
Q.push(i);
while(!Q.empty() && tme[Q.top()] + i - Q.top() > L)
Q.pop();
if(!Q.empty()){
// printf("%d %d\n", Q.top(), i);
q[i].PB(Q.top());
}
}
for(int i = 0;i < 30;i++){
COST = (LO + HI) / 2;
int odg = probaj().Y;
if(odg == d) break;
// printf("LO = %lld HI = %lld\n", LO, HI);
if(odg < d)
HI = COST;
else
LO = COST;
}
//printf("COST = %lld\n", COST);
pii fin = probaj();
//printf("%d %d\n", fin.X, fin.Y);
printf("%lld\n", (get_cost(fin) - COST * d) / 100000LL);
return 0;
}
