#include<cmath>
#include<cstdio>
#include<cstring>
#include<iostream>
#include<algorithm>
#include<queue>
#define MAXN 500005
#define LOG 20
#define max(x, y) ((x) > (y) ? (x) : (y))
#define min(x, y) ((x) < (y) ? (x) : (y))
long long sum[MAXN], table[MAXN][LOG];
namespace RMQ {
    void init(int n) {
        for (int i = 1; i <= n; i++) table[i][0] = i;
        for (int j = 1; (1 << j) <= n; j++)
            for (int i = 1; i + (1 << j) - 1 <= n; i++) {
                int x = table[i][j - 1], y = table[i + (1 << (j - 1))][j - 1];
                table[i][j] = sum[x] > sum[y] ? x : y;
            }
    }
    int query(int l, int r) {
        int k = log2(r - l + 1);
        int x = table[l][k], y = table[r - (1 << k) + 1][k];
        return sum[x] > sum[y] ? x : y;
    }
}
struct element {
    int o, l, r, t;
    element() {}
    element(int o, int l, int r) : o(o), l(l), r(r), t(RMQ::query(l, r)) {}
    friend bool operator < (const element& a, const element& b) {
        return sum[a.t] - sum[a.o - 1] < sum[b.t] - sum[b.o - 1];
    }
};
std::priority_queue< element > Q;
int main() {
    int n, k, L, R;
    scanf("%d%d%d%d", &n, &k, &L, &R);
    for (int i = 1; i <= n; i++) {
        scanf("%lld", &sum[i]);
        sum[i] += sum[i - 1];
    }
    RMQ::init(n);
    for (int i = 1; i <= n; i++)
        if (i + L - 1 <= n) 
            Q.push(element(i, i + L - 1, min(i + R - 1, n)));
    long long ans = 0;
    while (k--) {
        int o = Q.top().o, l = Q.top().l, r = Q.top().r, t = Q.top().t;
        Q.pop();
        ans += sum[t] - sum[o - 1];
        if (l != t) Q.push(element(o, l, t - 1)); 
        if (t != r) Q.push(element(o, t + 1, r));
    }
    printf("%lld\n", ans);
    return 0;
}