#include <bits/stdc++.h>

using namespace std;

using i64 = int64_t;

const i64 MOD = 1e9+7;

const i64 INF = 1e18+7;

// pythonのrangeのような範囲for文用のclass for(const auto& i : Range<>(10)) のように書く
template <typename T = i64>
struct Range{
    struct iterator{
        T value;
        const T step, last;
        const T& operator*(){return value;}
        iterator(T value, T step, T last) :
            value(value),
            step(step),
            last(last)
        {
        }
        iterator operator++(){value = step < static_cast<T>(0) ? max(value + step, last) : min(value + step, last); return *this;}
        bool operator!=(const iterator& x){return value != x.value;}
    };
    const T start, last, step;

    Range(const T start, const T last, const T step = static_cast<T>(1)) :
        start(start),
        last(last),
        step(step)
    {
    }

    Range(const T last) :
        start(0),
        last(last),
        step(1)
    {
    }

    iterator begin(){return iterator(start, step, last);}
    iterator end(){return iterator(last, step, last);}
};

// lambda式を用いた再帰
template <typename F>
struct FixPoint{
    const F _f;
    FixPoint(F&& f) : _f(forward<F>(f)){}

    template<typename... Types>
    decltype(auto) operator()(Types&&... args) const{
        return _f(*this, forward<Types>(args)...);
    }
};

template <typename F>
static decltype(auto) makeRec(F&& f){
    return FixPoint<F>(forward<F>(f));
}

// 多次元vectorの一斉初期化 makeVector<i64, 0>(a, b, ...)のように書く
template <typename T, T Value = T()>
vector<T> makeVector(size_t x){
    return vector<T>(x, T(Value));
}

template <typename T, T Value = T(), typename... Types>
auto makeVector(size_t x, Types... args){
    return vector<decltype(makeVector<T, Value>(args...))>(x, makeVector<T, Value>(args...));
}

// 最大値を更新し、更新できた時にはtrueを返す
template <typename T = i64>
bool chmax(T& a, T b){
    if(a < b){
        a = b;
        return true;
    }
    return false;
}

// 同様に最小値を更新する
template <typename T = i64>
bool chmin(T& a, T b){
    if(a > b){
        a = b;
        return true;
    }
    return false;
}

// 行数と変数名、値をclogに表示するデバッグ用print
#define dump(x) fprintf(stderr, "line =%4d, name =%7s , ", __LINE__, #x); clog << "value = " << x << endl;

// 同様の配列向けデバッグ用print
#define vecdump(x) fprintf(stderr, "line =%4d, name =%7s\n", __LINE__, #x); _dump_macro(x);

void _dump(int, string& x){
    clog << x << endl;
}

template <typename T>
void _dump(bool, T& x){
    clog << x << " ";
}

template <typename T, typename U = typename T::iterator>
void _dump(int, T& x){

    for(auto& elm : x)
        _dump(0, elm);

    clog << endl;
}

template <typename T>
void _dump_macro(T& x){
    _dump(0, x);
}

// input用の関数群
void _input(int, string& x){
    cin >> x;
}

template <typename T>
void _input(bool, T& x){
    cin >> x;
}

template <typename T, typename U = typename T::iterator>
void _input(int, T& x){

    for(auto& elm : x)
        _input(0, elm);
}

template <typename T>
void input_single(T& x){
    _input(0, x);
}

auto input(){}

template <typename T, typename... Types>
void input(T& value, Types&&... args){
    input_single(value);
    input(forward<Types>(args)...);
};

void _pararell_input(size_t){}

template <typename T, typename... Types>
void _pararell_input(size_t index, T& value, Types&&... args){
    input(value[index]);
    _pararell_input(index, forward<Types>(args)...);
}

template <typename... Types>
void pararell_input(size_t count, Types&&... args){
    for(const auto& i : Range<>(count))
        _pararell_input(i, forward<Types>(args)...);
}

template<typename T, typename U>
struct Segtree{
    const int n;
    const T op_t;
    const U op_u;
    vector<T> elm;
    vector<U> lazy;
    vector<int> length;
    function<T(T, T)> f;
    function<T(T, U, int)> g;
    function<U(U, U)> h;

    Segtree(int n, vector<T>& init, function<T(T, T)> f, function<T(T, U, int)> g, function<U(U, U)> h, T op_t = T(), U op_u = U()) :
        n(n),
        op_t(op_t),
        op_u(op_u),
        elm(2 * n, 0),
        lazy(2 * n, op_u),
        length(2 * n, 0),
        f(f),
        g(g),
        h(h)
    {
        for(int i = 0; i < n; ++i)
            elm[n + i] = init[i];
        for(int i = n - 1; i > 0; --i){
            elm[i] = f(elm[2 * i], elm[2 * i + 1]);
            length[i] = length[2 * i] + 1;
        }
    }

    vector<int> get_list(int x, int y){

        vector<int> ret_list;
        for(x += n, y += n - 1; x; x >>= 1, y >>= 1){
            ret_list.emplace_back(x);
            if(x != y)
                ret_list.emplace_back(y);
        }

        return ret_list;
    }

    void eval(int x){

        elm[x] = g(elm[x], lazy[x], 1 << length[x]);
        if(x < n){
            lazy[2 * x] = h(lazy[2 * x], lazy[x]);
            lazy[2 * x + 1] = h(lazy[2 * x + 1], lazy[x]);
        }
        lazy[x] = op_u;
    }

    void update(int x, int y, U val){

        vector<int> index_list = get_list(x, y);
        for(int i = index_list.size() - 1; i >= 0; --i)
            eval(index_list[i]);

        for(x += n, y += n - 1; x <= y; x >>= 1, y >>= 1){
            if(x & 1){
                lazy[x] = h(lazy[x], val);
                eval(x++);
            }
            if(!(y & 1)){
                lazy[y] = h(lazy[y], val);
                eval(y--);
            }
        }

        for(auto index : index_list){
            if(index < n){
                eval(2 * index);
                eval(2 * index + 1);
                elm[index] = f(elm[2 * index], elm[2 * index + 1]);
            }
        }
    }

    T get(int x, int y){

        vector<int> index_list = get_list(x, y);
        for(int i = index_list.size() - 1; i >= 0; --i)
            eval(index_list[i]);

        T val = op_t;
        for(x += n, y += n - 1; x <= y; x >>= 1, y >>= 1){
            if(x & 1){
                eval(x);
                val = f(val, elm[x++]);
            }
            if(!(y & 1)){
                eval(y);
                val = f(val, elm[y--]);
            }
        }
        return val;
    }
};

signed main(){

    cin.tie(0);
    ios::sync_with_stdio(false);
    cout << fixed << setprecision(20);

    int n, q, sa, sb;
    input(n, q, sa, sb);
    vector<int> a(q);
    input(a);
    --sa, --sb;
    for(auto& x : a)
        --x;

    vector<i64> vll(n, INF), vrr(n, INF);

    vector<int> v_r(n);
    iota(v_r.begin(), v_r.end(), 0);
    auto v_l = v_r;
    reverse(v_l.begin(), v_l.end());

    for(const auto& i : Range<>(n - 1, -1, -1)){
        vll[i] += v_l[i];
        vrr[i] += v_r[i];
    }


    vll[sb] -= INF;
    vrr[sb] -= INF;

    Segtree<i64, i64> seg_l(n, vll, [](i64 x, i64 y){return min(x, y);}, [](i64 x, i64 y, int){return x + y;}, [](i64 x, i64 y){return x + y;}, 2 * INF);
    Segtree<i64, i64> seg_r(n, vrr, [](i64 x, i64 y){return min(x, y);}, [](i64 x, i64 y, int){return x + y;}, [](i64 x, i64 y){return x + y;}, 2 * INF);

    int prev = sa;
    i64 sum = 0;
    for(auto& x : a){

        i64 dist = abs(x - prev);
        sum += dist;
        i64 tmp = 2 * INF;

        chmin(tmp, seg_l.get(0, x) - v_l[x]);
        chmin(tmp, seg_r.get(x, n) - v_r[x]);

        /*
        seg_l.update(0, n, dist);
        seg_r.update(0, n, dist);
        */

        // tmpは操作後の理論値
        seg_l.update(prev, prev + 1, tmp - seg_l.get(prev, prev + 1) + v_l[prev] - dist);
        seg_r.update(prev, prev + 1, tmp - seg_r.get(prev, prev + 1) + v_r[prev] - dist);

        prev = x;
    }


    i64 ans = INF;
    for(const auto& i : Range<>(n)){
        chmin(ans, seg_l.get(i, i + 1) - v_l[i]);
        chmin(ans, seg_r.get(i, i + 1) - v_r[i]);
    }
    cout << ans + sum << endl;

}


Measured memory_bytes: 23424