#include <bits/stdc++.h>
#define SZ(x) ((int)x.size())
#define fi first
#define se second
#define pb push_back
#define FOR(i, a, b) for (int i = a, _b = b; i <= _b; ++i)
#define FORD(i, a, b) for (int i = a, _b = b; i >= _b; --i)
#define FORLL(i, a, b) for (ll i = a, _b = b; i <= _b; ++i)
#define FORDLL(i, a, b) for (ll i = a, _b = b; i >= _b; --i)
#define all(x) x.begin(), x.end()
#define uni(x) sort(all(x)), x.erase(unique(all(x)), x.end())
using namespace std;
typedef long long ll;
typedef unsigned long long ull;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;
#define dbg(...) debug(#__VA_ARGS__, __VA_ARGS__)
template<typename T>
void __print_one(const char *&s, const T &x)
{
while (*s == ' ') ++s;
const char *p = s;
int bal = 0;
while (*s)
{
if (*s == '(') ++bal;
else if (*s == ')') --bal;
else if (*s == ',' && bal == 0) break;
++s;
}
cerr.write(p, s - p) << " = " << x;
if (*s == ',')
{
++s;
cerr << " , ";
}
}
template<typename... Args>
void debug(const char *s, Args... args)
{
cerr << "[ ";
int dummy[] = { 0 , ( __print_one(s, args) , 0 )... };
(void)dummy;
cerr << " ]\n\n";
}
template<class X>
bool maximize(X &a, X b)
{
if (a < b)
{
a = b;
return true;
}
return false;
}
template<class X>
bool minimize(X &a, X b)
{
if (a > b)
{
a = b;
return true;
}
return false;
}
// --------------------------------------------------------------------------------------------
constexpr int maxn = 105;
int n, L, R, K, a[maxn], sumA, preL[10005], preR[10005];
unordered_map<int, int> dpL[maxn][maxn], dpR[maxn][maxn];
// --------------------------------------------------------------------------------------------
void solve()
{
cin >> n >> L >> R >> K;
FOR(i, 1, n)
{
cin >> a[i];
}
FOR(i, L, R)
sumA += a[i];
if (L > 1)
{
dpL[1][L][0] = 0;
FOR(i, 1, L)
FOR(j, L, R + 1)
for (const auto &p : dpL[i][j])
{
int k = p.fi, w = p.se;
minimize(dpL[i][j + 1][k], w);
minimize(dpL[i + 1][j][k], w);
int new_k = k + abs(j - i), cost = - a[j] + a[i];
if (k + abs(j - i) <= K)
minimize(dpL[i + 1][j + 1][new_k], w + cost);
}
}
if (R < n)
{
dpR[n][R][0] = 0;
FORD(i, n, R)
FORD(j, R, L - 1)
for (const auto &p : dpR[i][j])
{
int k = p.fi, w = p.se;
if (j - 1 >= 0) minimize(dpR[i][j - 1][k], w);
if (i - 1 >= 0) minimize(dpR[i - 1][j][k], w);
int new_k = k + abs(j - i), cost = - a[j] + a[i];
if (k + abs(j - i) <= K && i - 1 >= 0 && j - 1 >= 0)
{
minimize(dpR[i - 1][j - 1][new_k], w + cost);
}
}
}
// dbg(dpR[R][L - 1][3]);
int res = 0;
FOR(i, L - 1, R)
{
FOR(k, 0, K)
{
preL[k] = dpL[L][i + 1][k];
if (k)
minimize(preL[k], preL[k - 1]);
}
FOR(k, 0, K)
{
preR[k] = dpR[R][i][k];
if (k)
minimize(preR[k], preR[k - 1]);
res = min(res, preR[k] + preL[K - k]);
}
}
cout << sumA + res;
}
signed main()
{
ios_base::sync_with_stdio(false); cin.tie(NULL); cout.tie(NULL);
#define TASK "TEST"
if (fopen(TASK".INP", "r"))
{
freopen(TASK".INP", "r", stdin);
freopen(TASK".OUT", "w", stdout);
}
solve();
return 0;
}
