#include <bits/stdc++.h>
#pragma GCC optimize("O3")
using namespace std;
#define ll int
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;
l--;
r--;
vector<ll>v(n);
for (int i=0 ; i<n ;i++) cin>>v[i];
ll sz = (r-l+1);
ll val = 0;
for (int i=l ; i<=r ; i++) val += i;
ll res = INT_MAX;
for (int m=0 ; m<(1<<n) ; m++)
{
if (__builtin_popcount(m)!=sz) continue;
ll s1 = val;
ll sm = 0;
for (int j=0 ; j<n ; j++)
{
if ((1<<j)&m)
{
sm += v[j];
s1 -= j;
}
}
if (s1<=k) res = min(res, sm);
}
cout<<res<<endl;
}
int main()
{
ios_base::sync_with_stdio(false);
cin.tie(nullptr);
ll tt = 1;
// cin>>tt;
while (tt--)
{
solve();
}
return 0;
}
