#include <bits/stdc++.h>
#pragma GCC optimize("O3")
using namespace std;
#define ll long long
ll mod = 1e9+7;
//mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
ll binpow(ll a, ll b)
{
ll res = 1;
while (b>0)
{
if (b&1)
res = (res*a)%mod;
a = (a*a)%mod;
b>>=1;
}
return res;
}
ll gcd(ll x, ll y)
{
if (y==0)
return x;
return gcd(y, x%y);
}
void solve()
{
ll n,l,r,k;
cin>>n>>l>>r>>k;
vector<ll>v(n+1);
for (int i=1 ; i<=n ; i++) cin>>v[i];
ll cst = 0;
for (int i=l ; i<=r ; i++) cst += i;
vector<vector<ll>>dp(n+1, vector<ll>(cst+1, INT_MAX));
ll sz = cst+1;
dp[0][0] = 0;
cst -= k;
for (int i=1 ;i <=n ;i++)
{
for (int j=sz-1 ; j>=0 ; j--)
{
if (j+i>=sz) continue;
for (int k1=n-1 ; k1>=0 ; k1--)
{
if (dp[k1][j]!=INT_MAX)
dp[k1+1][j+i] = min(dp[k1+1][j+i], dp[k1][j]+v[i]);
}
}
}
// cout<<dp[1]
ll res = INT_MAX;
for (int i=max(cst, 0ll) ; i<sz ; i++) res = min(res, dp[(r-l+1)][i]);
cout<<res;
}
int main()
{
ios_base::sync_with_stdio(false);
cin.tie(nullptr);
ll tt = 1;
// cin>>tt;
while (tt--)
{
solve();
}
return 0;
}
