//author : FatihCihan
#include <bits/stdc++.h>
using namespace std;
#define all(v) v.begin() , v.end()
#define sz(a) (int)a.size()
using namespace std;
const int N = 4010;
int range[N][N];
int v[N];
int dp[N][N];
int n, d, t;
void solve(){
cin >> n >> d >> t;
memset(range, -1, sizeof range);
for(int i = 1;i <= n;i++) cin >> v[i];
for(int i = 0;i <= d;i++){
dp[0][i] = 0;
}
for(int d = 0;d <= n;d++){
for(int l = 1;l <= n;l++){
int r = l+d;
if(r > n) continue;
if(v[l] > t) {range[l][r] = (l == r ? 0 : range[l+1][r]); continue;}
int sum = t - v[l] + 1;
int con = 1;
bool piroca = false;
for(int i = l+1;i < l+sum;i++){
if(i > r) break;
if(v[i] <= v[l]+con){
range[l][r] = con + range[i][r];
piroca = true;
break;
}
con++;
}
if(piroca) continue;
range[l][r] = con + (l+sum > r ? 0 : range[l+sum][r]);
}
}
for(int pos = 1;pos <= n;pos++){
for(int qtd = 0;qtd <= d;qtd++){
dp[pos][qtd] = range[1][pos];
if(qtd == 0) continue;
for(int i = pos-1;i >= 0;i--){
dp[pos][qtd] = min(dp[pos][qtd], dp[i][qtd-1] + range[i+1][pos]);
}
}
}
cout << dp[n][d] << '\n';
}
signed main(){
ios_base::sync_with_stdio(0);cin.tie(0);
int testcase = 1;//cin >> testcase;
while(testcase--)solve();
cerr << 1000.0 * clock() / CLOCKS_PER_SEC << " ms" << endl;
}
