const int N = 400005;
const int LG = 21;
const long long MOD = 1e9 + 7;
const long long INF = 1e9;
const long long INFLL = 1e18;

#include <iostream>
#include <vector>
#include <string>
#include <map>
#include <set>
#include <algorithm>
#include <cmath>
#include <time.h>
#include <unordered_set>
#include <bitset>
#include <deque>

using namespace std;

typedef long long ll;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;
typedef vector<ll> vi;

#define forn(i, n) for (int (i) = 0; (i) != (n); (i)++)
#define all(v) (v).begin(), (v).end()
#define rall(v) (v).rbegin(), (v).rend()
#define popcount(x) __builtin_popcount(x)
#define popcountll(x) __builtin_popcountll(x)
#define fi first
#define se second
#define re return
#define uniq(x) sort(all(x)); (x).resize(unique(all(x)) - (x).begin())

#ifdef LOCAL
#define dbg(x) cerr << __LINE__ << " " << #x << " " << x << endl
#define ln cerr << __LINE__ << endl
#else
#define dbg(x) void(0)
#define ln void(0)
#endif // LOCAL

int cx[4] = {-1, 0, 1, 0};
int cy[4] = {0, -1, 0, 1};

ll inq(ll x, ll y)
{
    if (!y) re 1 % MOD;
    ll l = inq(x, y / 2);
    if (y % 2) re l * l % MOD * x % MOD;
    re l * l % MOD;
}

ll rev(ll x)
{
    return inq(x, MOD - 2);
}

bool __precomputed_combinatorics = 0;
vector<ll> __fact, __ufact, __rev;

void __precompute_combinatorics()
{
    __precomputed_combinatorics = 1;
    __fact.resize(N);
    __ufact.resize(N);
    __rev.resize(N);
    __rev[1] = 1;
    for (int i = 2; i < N; i++) __rev[i] = MOD - __rev[MOD % i] * (MOD / i) % MOD;
    __fact[0] = 1, __ufact[0] = 1;
    for (int i = 1; i < N; i++) __fact[i] = __fact[i - 1] * i % MOD, __ufact[i] = __ufact[i - 1] * __rev[i] % MOD;
}

ll fact(int x)
{
    if (!__precomputed_combinatorics) __precompute_combinatorics();
    return __fact[x];
}

ll cnk(int n, int k)
{
    if (!__precomputed_combinatorics) __precompute_combinatorics();
    return __fact[n] * __ufact[n - k] % MOD * __ufact[k] % MOD;
}

int n, q, a, b;
int x[500000];

struct Node{
    ll update;
    ll minCostL, minCostR;
};

Node Tree[4 * N];

void build(int L = 0, int R = n, int V = 0)
{
    if (L + 1 == R)
    {
        Tree[V].minCostR = n - L;
        Tree[V].minCostL = L;
        if (L != a)
        {
            Tree[V].minCostR += INFLL;
            Tree[V].minCostL += INFLL;
        }
        return;
    }
    int M = (L + R) / 2;
    build(L, M, 2 * V + 1);
    build(M, R, 2 * V + 2);
    Tree[V].minCostL = min(Tree[2 * V + 1].minCostL, Tree[2 * V + 2].minCostL);
    Tree[V].minCostR = min(Tree[2 * V + 1].minCostR, Tree[2 * V + 2].minCostR);
}

void Add(int c)
{
    Tree[0].minCostL += c;
    Tree[0].minCostR += c;
    Tree[0].update += c;
}

void Push(int V)
{
    Tree[2 * V + 1].minCostL += Tree[V].update;
    Tree[2 * V + 1].minCostR += Tree[V].update;
    Tree[2 * V + 1].update += Tree[V].update;
    Tree[2 * V + 2].minCostL += Tree[V].update;
    Tree[2 * V + 2].minCostR += Tree[V].update;
    Tree[2 * V + 2].update += Tree[V].update;
    Tree[V].update = 0;
}

ll GetMinL(int l, int r, int L = 0, int R = n, int V = 0)
{
    if (r <= L || R <= l) return 2 * INFLL;
    if (l <= L && R <= r) return Tree[V].minCostL;
    int M = (L + R) / 2;
    Push(V);
    return min(GetMinL(l, r, L, M, 2 * V + 1),
    GetMinL(l, r, M, R, 2 * V + 2));
}

ll GetMinR(int l, int r, int L = 0, int R = n, int V = 0)
{
    if (r <= L || R <= l) return 2 * INFLL;
    if (l <= L && R <= r) return Tree[V].minCostR;
    int M = (L + R) / 2;
    Push(V);
    return min(GetMinR(l, r, L, M, 2 * V + 1),
    GetMinR(l, r, M, R, 2 * V + 2));
}

void Change(int p, ll nv, int L = 0, int R = n, int V = 0)
{
    if (L + 1 == R)
    {
        Tree[V].minCostL = L + nv;
        Tree[V].minCostR = n - L + nv;
        return;
    }
    int M = (L + R) / 2;
    Push(V);
    if (p < M) Change(p, nv, L, M, 2 * V + 1);
    else Change(p, nv, M, R, 2 * V + 2);
    Tree[V].minCostL = min(Tree[2 * V + 1].minCostL, Tree[2 * V + 2].minCostL);
    Tree[V].minCostR = min(Tree[2 * V + 1].minCostR, Tree[2 * V + 2].minCostR);
}

void Query(int x, int y)
{
    ll RP = GetMinL(y, n) - y;
    ll LP = GetMinR(0, y + 1) - n + y;
    Add(abs(x - y));
    Change(x, min(LP, RP));
}

ll answer()
{
    ll res = INFLL;
    for (int i = 0; i < n; i++)
    {
        //cout << i << " " << GetMinL(i, i + 1) - i << "\n";
        res = min(res, GetMinL(i, i + 1) - i);
    }
    return res;
}

signed main()
{
    srand(time(NULL));
    #ifdef ONLINE_JUDGE
        ios_base::sync_with_stdio(false);
        cin.tie(0);
        cout.tie(0);
    #endif // ONLINE_JUDGE
    cin >> n >> q >> a, a--;
    for (int i = 0; i <= q; i++) cin >> x[i], x[i]--;
    build();
    for (int i = 0; i < q; i++)
    {
        Query(x[i], x[i + 1]);
    }
    cout << answer() << "\n";
}

/* Note:
Check constants at the beginning of the code.
N is set to 4e5 but be careful in problems with large constant factor.
Check corner cases.
No def int long long for now.
*/


Measured memory_bytes: 16640