#include <bits/stdc++.h>
using namespace std;
#define FOR(i, begin, end) for(int i=(begin);i<(end);i++)
#define IFOR(i, begin, end) for(int i=(end)-1;i>=(begin);i--)
#define REP(i, n) FOR(i,0,n)
#define IREP(i, n) IFOR(i,0,n)

using lint = long long;

int N, Q, A, B;
constexpr int Nmax = 200000;

array<lint, Nmax + 1> x;

template <typename VAL, typename DVAL>
struct LazySegTree
{
    int N;
    int head;

    vector<VAL> val;
    vector<DVAL> dval;
    VAL I_val;
    DVAL I_dval;

    using vv2v = function<VAL(const VAL&, const VAL&)>;
    using d2d = function<void(DVAL&, const DVAL&)>;
    using d2v = function<void(VAL&, const DVAL&)>;
    vv2v merge_val;
    d2d add_dval;
    d2v refl_dval;

    LazySegTree(vector<VAL> &val_init, VAL val_default, DVAL dval_default,
                vv2v f, d2d dadd, d2v dreflect)
            : N(val_init.size()), I_val(val_default), I_dval(dval_default),
              merge_val(f),
              add_dval(dadd),
              refl_dval(dreflect)
    {
        int N_tmp = 1;
        while (N_tmp < N) N_tmp <<= 1;
        val = vector<VAL>(N_tmp*2, I_val);
        dval = vector<DVAL>(N_tmp*2, I_dval);
        head = N_tmp - 1;
        for (int i=0; i<N; i++) val[head+i] = val_init[i];
        for (int pos=head-1; pos>=0; pos--) val[pos] = merge_val(val[pos*2+1], val[pos*2+2]);
    }

    void resolve_dval(int pos, int l, int r) { // posで遅延を解消して子孫に押し付ける
        refl_dval(val[pos], dval[pos]);
        if (pos < head)
        {
            add_dval(dval[pos*2+1], dval[pos]);
            add_dval(dval[pos*2+2], dval[pos]);
        }
        dval[pos] = I_dval;
    }

    void update(int begin, int end, DVAL dval_q) { update(begin, end, dval_q, 0, 0, head+1); }
    void update(int begin, int end, DVAL dval_q, int pos, int l, int r)
    {
        // 後でリファクタリング
        if (begin <= l && r <= end) { // 担当区間全部使う
            add_dval(dval[pos], dval_q);
            resolve_dval(pos, l, r);
        }
        else if (begin < r && l < end) { // 少なくともどこかで交差
            resolve_dval(pos, l, r);
            update(begin, end, dval_q, pos*2+1, l, (l+r)/2);
            update(begin, end, dval_q, pos*2+2, (l+r)/2, r);
            val[pos] = merge_val(val[pos*2+1], val[pos*2+2]);
        }
        else resolve_dval(pos, l, r);
    }

    VAL getvalue(int begin, int end) { return getvalue(begin, end, 0, 0, head+1); }
    VAL getvalue(int begin, int end, int pos, int l, int r)
    {
        resolve_dval(pos, l, r);
        if (begin <= l && r <= end) return val[pos];
        else if (begin<r && l<end) {
            VAL vl = getvalue(begin, end, pos*2+1, l, (l+r)/2);
            VAL vr = getvalue(begin, end, pos*2+2, (l+r)/2, r);
            val[pos] = merge_val(val[pos*2+1], val[pos*2+2]);
            return merge_val(vl, vr);
        }
        else return I_val;
    }
};

struct tri
{
    lint x, xp, xm;
    tri() {}
    tri(lint a, lint b, lint c) : x(a), xp(b), xm(c) {}
    void setval(lint y, int i) {
        x = y;
        xp = y + i;
        xm = y - i;
    }
};

constexpr lint INF = 1000000000000;

int main()
{
    cin >> N >> Q >> A >> B;
    x[0] = A;
    REP(i, Q) scanf("%lld", &x[i + 1]);

    vector<tri> init(N + 1);
    REP(i, N + 1) {
        init[i].x = INF;
        init[i].xp = INF + i;
        init[i].xm = INF - i;
    }
    init[B].x = 0LL;
    init[B].xp = B;
    init[B].xm = -B;

    LazySegTree<tri, lint> rmq(init, tri(INF * 2, INF * 2, INF * 2), 0, 
                            [](tri a, tri b){return tri(min(a.x, b.x), min(a.xp, b.xp), min(a.xm, b.xm));}, // 本情報のmerge
                            [](lint &a, lint b){a += b;}, // 遅延情報の子孫への伝播
                            [](tri &a, lint b){a.x += b; a.xp += b; a.xm += b;}); // 遅延情報の本情報への反映

    REP(i, Q)
    {
        tri q1 = rmq.getvalue(x[i + 1], N + 1);
        tri q2 = rmq.getvalue(1, x[i + 1] + 1);
        lint newval = min(q1.xp - x[i + 1], q2.xm + x[i + 1]);

        rmq.update(1, N + 1, abs(x[i + 1] - x[i]));
        lint def = rmq.getvalue(x[i], x[i] + 1).x;
        rmq.update(x[i], x[i] + 1, newval - def);
    }
    cout << rmq.getvalue(1, N + 1).x << endl;
}


Measured memory_bytes: 22912