#include <cstdio>
#include <cstring>
#include <algorithm>
#include <vector>
#include <array>
#include <utility>
#include <queue>
#include <cmath>
#include <functional>
#define fileio(PATH) (freopen(PATH ".in", "r", stdin), freopen(PATH ".out", "w", stdout))
using std::vector, std::array, std::pair, std::priority_queue;
using ll = long long;
using ull = unsigned long long;
const ll INF = 0x3f3f3f3f3f3f3f3f;
struct DbHeap
{
    priority_queue<ll> st;
    priority_queue<ll, vector<ll>, std::greater<ll>> ed;
    ll sum;
    void push(ll x)
    {
        if(st.size() && st.top() >= x)
            st.push(x), sum += x;
        else
            ed.push(x);
        return;
    }
    ll prefix_sum(int k)
    {
        while((int)st.size() < k)
        {
            ll x = ed.top();
            ed.pop();
            st.push(x);
            sum += x;
        }
        while((int)st.size() > k)
        {
            ll x = st.top();
            st.pop();
            ed.push(x);
            sum -= x;
        }
        return sum;
    }
};
vector<ll> solve_core(vector<ll> x, int a, int b)
{
    int n = x.size();
    vector<ll> res(n, INF);
    DbHeap cur = {};
    for(int i = 0, now = 0;i < n;++i)
        if(x[i] > 0)
        {
            ++now;
            ll bas = 2 * x[n - 1] - x[0] - x[i] + std::abs(x[0]);
            res[i] = bas + 2 * cur.prefix_sum(std::max(0, now - b));
            if(i > 0 && x[i - 1] > 0)
                cur.push(x[i] - x[i - 1]);
        }
    return res;
}
vector<ll> solve(vector<ll> x, int a, int b)
{
    int n = x.size();
    if(a > b)
    {
        std::reverse(x.begin(), x.end());
        std::swap(a, b);
        for(int i = 0;i < n;++i)
            x[i] = -x[i];
        vector<ll> res = solve(x, a, b);
        std::reverse(res.begin(), res.end());
        return res;
    }
    vector<ll> res(n, INF);
    if(a == 0)
    {
        if(x[0] > 0)
            res[n - 1] = x[n - 1];
        return res;
    }
    else if(a == 1)
    {
        if(x[0] > 0)
        {
            for(int i = 0;i < n - 2;++i)
                res[n - 1] = std::min(res[n - 1], x[n - 1] + 2 * (x[i + 1] - x[i]));
            for(int i = 0;i < n - 1;++i)
                res[i] = 2 * x[n - 1] - x[i];
        }
        else
        {
            res[n - 1] = x[n - 1] - 2 * x[0];
            for(int i = 0;i < n - 1;++i)
                if(x[i + 1] > 0)
                    res[i] = 2 * (x[n - 1] - x[0]) + x[i];
        }
        return res;
    }
    res = solve_core(x, a, b);
    std::reverse(x.begin(), x.end());
    std::swap(a, b);
    for(int i = 0;i < n;++i)
        x[i] = -x[i];
    vector<ll> res2 = solve_core(x, a, b);
    std::reverse(res2.begin(), res2.end());
    for(int i = 0;i < n;++i)
        res[i] = std::min(res[i], res2[i]);
    return res;
}
int main(void)
{
    // fileio("postman");
    int n, a, b, ty;
    scanf("%d%d%d", &n, &a, &ty), b = n - a;
    vector<ll> x(n);
    for(int i = 0;i < n;++i)
        scanf("%lld", &x[i]);
    if(n == 1)
        ty = 1;
    if(ty == 1)
    {
        std::sort(x.begin(), x.end());
        vector<ll> res = solve(x, a, b);
        ll ans = *std::min_element(res.begin(), res.end());
        printf("%lld\n", ans == INF ? -1ll : ans);
    }
    else
    {
        vector<ll> y = x;
        y.pop_back();
        std::sort(y.begin(), y.end());
        ll ans = INF;
        if(a > 0)
        {
            vector<ll> res = solve(y, a - 1, b);
            for(int i = 0;i < n - 1;++i)
                if(res[i] != INF && y[i] > x[n - 1])
                    ans = std::min(ans, res[i] + y[i] - x[n - 1]); //, fprintf(stderr, "%d %lld\n", i, res[i] + y[i] - x[n - 1]);
        }
        if(b > 0)
        {
            vector<ll> res = solve(y, a, b - 1);
            for(int i = 0;i < n - 1;++i)
                if(res[i] != INF && y[i] < x[n - 1])
                    ans = std::min(ans, res[i] + x[n - 1] - y[i]); //, fprintf(stderr, "%d %lld\n", i, res[i] - y[i] + x[n - 1]);
        }
        printf("%lld\n", ans == INF ? -1ll : ans);
    }
    return 0;
}