#include <bits/stdc++.h>
using namespace std;
const int MAX_N = 4000;
const int MAX_D = MAX_N;
const int INF = MAX_N + 1;
int minPrisoners[MAX_N + 1][MAX_D + 1], t[MAX_N + 1], firstLower[MAX_N + 1];
struct SegTree {
int n, ls, rs;
vector<int> segTree, lazy;
void init( int _n, int _ls, int _rs ) {
n = _n;
ls = _ls;
rs = _rs;
segTree.resize( 4 * n );
lazy.resize( 4 * n );
for ( int v = 0; v < 4 * n; v++ )
segTree[v] = lazy[v] = 0;
}
void propag( int v, int l, int r ) {
segTree[v] += lazy[v];
if ( l != r ) {
lazy[v * 2 + 1] += lazy[v];
lazy[v * 2 + 2] += lazy[v];
}
lazy[v] = 0;
}
void update( int v, int l, int r, int lu, int ru, int x ) {
propag( v, l, r );
if ( l > ru || r < lu )
return;
if ( lu <= l && r <= ru ) {
lazy[v] += x;
propag( v, l, r );
return;
}
int mid = (l + r) / 2;
update( v * 2 + 1, l, mid, lu, ru, x );
update( v * 2 + 2, mid + 1, r, lu, ru, x );
segTree[v] = min( segTree[v * 2 + 1], segTree[v * 2 + 2] );
}
void update( int l, int r, int x ) {
update( 0, ls, rs, l, r, x );
}
int query( int v, int l, int r, int lq, int rq ) {
propag( v, l, r );
if ( l > rq || r < lq )
return INF;
if ( lq <= l && r <= rq )
return segTree[v];
int mid = (l + r) / 2;
return min( query( v * 2 + 1, l, mid, lq, rq ), query( v * 2 + 2, mid + 1, r, lq, rq ) );
}
} prisoners;
int main() {
int n, d, s;
cin >> n >> d >> s;
d++;
for ( int i = 1; i <= n; i++ ) {
cin >> t[i];
t[i] -= i;
}
for ( int i = 1; i <= n; i++ ) {
for ( int j = i; j >= 1; j-- ) {
if ( t[j] <= s - i ) {
firstLower[i] = j;
break;
}
}
}
minPrisoners[0][0] = 0;
for ( int i = 1; i <= n; i++ )
minPrisoners[i][0] = INF;
for ( int k = 1; k <= d; k++ ) {
minPrisoners[0][k] = INF;
prisoners.init( n, 1, n );
for ( int i = 1; i <= n; i++ ) {
prisoners.update( i, i, minPrisoners[i - 1][k - 1] );
int minT = s;
prisoners.update( 1, firstLower[i], 1 );
minPrisoners[i][k] = prisoners.query( 0, 1, n, 1, i );
}
}
cout << minPrisoners[n][d] << "\n";
return 0;
}
