#include <bits/stdc++.h>
#ifndef DEBUG
#include "books.h"
#endif
using namespace std;
#define fi first
#define se second
#define mp make_pair
#define pb push_back
#define all(a) (a).begin(), (a).end()
using ll = long long;
using ull = unsigned long long;
using pii = pair<int, int>;
using pil = pair<int, ll>;
using pli = pair<ll, int>;
using pll = pair<ll, ll>;
using ld = long double;
template<typename T1, typename T2> bool chkmin(T1 &x, T2 y) {
return y < x ? (x = y, true) : false;
}
template<typename T1, typename T2> bool chkmax(T1 &x, T2 y) {
return y > x ? (x = y, true) : false;
}
void debug_out() {
cerr << endl;
}
template<typename T1, typename... T2> void debug_out(T1 A, T2... B) {
cerr << ' ' << A;
debug_out(B...);
}
template<typename T> void mdebug_out(T* a, int n) {
for (int i = 0; i < n; ++i) {
cerr << a[i] << ' ';
}
cerr << endl;
}
#ifdef DEBUG
#define debug(...) cerr << "[" << #__VA_ARGS__ << "]:", debug_out(__VA_ARGS__)
#define mdebug(a, n) cerr << #a << ": ", mdebug_out(a, n)
#else
#define debug(...) 1337
#define mdebug(a, n) 1337
#endif
template<typename T> ostream& operator << (ostream& stream, const vector<T> &v) {
for (auto& x : v) {
stream << x << ' ';
}
return stream;
}
template<typename T1, typename T2> ostream& operator << (ostream& stream, const pair<T1, T2>& p) {
return stream << p.first << ' ' << p.second;
}
const int INF32 = 1e9;
ll minimum_walk(vector<int> p, int s) {
int n = p.size();
vector<int> p_inv(n);
for (int i = 0; i < n; ++i) {
p_inv[p[i]] = i;
}
ll Ans = 0;
for (int i = 0; i < n; ++i) Ans += labs(p[i] - i);
vector<int> cyc(n, -1);
vector<int> cl(n, +INF32), cr(n, -INF32);
int C = 0;
for (int i = 0; i < n; ++i) {
if (p[i] != i && cyc[i] == -1) {
int c = C++;
cl[c] = cr[c] = i;
int x = i;
do {
cyc[x] = c;
chkmax(cr[c], x);
x = p[x];
} while (x != i);
}
}
if (!C) return 0;
vector<int> G[C];
vector<int> GR[C];
for (int c = 0; c < C; ++c) {
for (int i = cl[c]; i <= cr[c]; ++i) {
if (cyc[i] != -1 && cyc[i] != c) {
G[c].push_back(cyc[i]);
GR[cyc[i]].push_back(c);
}
}
}
vector<char> used(C, false);
vector<int> ord;
function<void(int)> dfs = [&](int v) {
used[v] = true;
for (int& u : G[v])
if (!used[u])
dfs(u);
ord.push_back(v);
};
for (int c = 0; c < C; ++c)
if (!used[c])
dfs(c);
reverse(all(ord));
vector<int> scc(C, -1);
int S = 0;
function<void(int)> dfs1 = [&](int v) {
scc[v] = S;
for (int& u : GR[v])
if (scc[u] == -1)
dfs1(u);
};
for (int& v : ord) {
if (scc[v] == -1) {
dfs1(v);
++S;
}
}
vector<char> src(S, true);
for (int c = 0; c < C; ++c) {
for (int d : G[c]) {
if (scc[c] != scc[d]) {
src[scc[d]] = false;
}
}
}
vector<int> sl(S, +INF32), sr(S, -INF32);
for (int c = 0; c < C; ++c) {
int s = scc[c];
chkmin(sl[s], cl[c]);
chkmax(sr[s], cr[c]);
}
vector<pii> segs;
for (int s = 0; s < S; ++s) {
if (src[s]) {
segs.emplace_back(sl[s], sr[s]);
}
}
sort(all(segs));
for (int i = 0; i + 1 < segs.size(); ++i) {
int r1 = segs[i].se;
int l2 = segs[i + 1].fi;
assert(r1 < l2);
Ans += 2 * (l2 - r1);
}
bool inside = false;
for (auto& g : segs) {
if (g.fi <= s && s <= g.se) {
inside = true;
break;
}
}
if (!inside) {
if (s < segs[0].fi) {
return Ans + 2 * labs(segs[0].fi - s);
} else if (s > segs.back().se) {
return Ans + 2 * labs(s - segs.back().se);
} else {
return Ans;
}
} else {
int Add = INF32;
{
int l = s;
while (cyc[l] == -1 || !src[scc[cyc[l]]]) --l;
if (l == s) return Ans;
/*vector<int> dp(n, 0);
for (int j = s - 1; j > l; --j) {
dp[j] = dp[j + 1];
if (p[j] != j && j < p_inv[j] && p_inv[j] <= s) {
chkmax(dp[j], p_inv[j] - j + dp[p_inv[j]]);
}
}
vector<int> dq(n, 0);
for (int j = l + 1; j <= s; ++j) {
dq[j] = dq[j - 1];
if (p[j] != j && l < p_inv[j] && p_inv[j] < j) {
chkmax(dq[j], j - p_inv[j] + dq[p_inv[j]]);
}
}*/
vector<int> cc(n, 0);
for (int c = 0; c < C; ++c) {
if (l < cl[c] && cl[c] <= s) {
for (int i = cl[c]; i < min(cr[c], s); ++i) {
cc[i] = 1;
}
}
}
chkmin(Add, 2 * (s - l) - 2 * accumulate(all(cc), 0));
}
{
int r = s;
while (cyc[r] == -1 || !src[scc[cyc[r]]]) ++r;
if (r == s) throw;
/*vector<int> dp(n, 0);
for (int j = s + 1; j < r; ++j) {
dp[j] = dp[j - 1];
if (p[j] != j && s <= p_inv[j] && p_inv[j] < j) {
chkmax(dp[j], j - p_inv[j] + dp[p_inv[j]]);
}
}
debug(r - s, dp[r - 1]);*/
vector<int> cc(n, 0);
for (int c = 0; c < C; ++c) {
if (s <= cr[c] && cr[c] < r) {
for (int i = max(s, cl[c]); i < cr[c]; ++i) {
cc[i] = 1;
}
}
}
chkmin(Add, 2 * (r - s) - 2 * accumulate(all(cc), 0));
}
return Ans + Add;
}
/*
if (s != 0) {
bool inside = false;
for (pii g : segs) {
if (g.fi <= s && s <= g.se) {
inside = true;
}
}
return (ll)inside;
}
/**/
return Ans;
}
#ifdef DEBUG
int32_t main() {
#ifdef DEBUG
freopen("in", "r", stdin);
#endif
ios::sync_with_stdio(0);
cin.tie(0);
int n, s;
cin >> n >> s;
vector<int> p(n);
for (auto& x : p) cin >> x;
cout << minimum_walk(p, s) << '\n';
return 0;
}
#endif
