//In the name of God
#include <bits/stdc++.h>
#include "books.h"
using namespace std;
typedef long long ll;
typedef pair<ll, ll> pll;
const ll maxn = 2e5 + 100;
const ll mod = 1e9 + 7;
const ll inf = 1e18;
#define pb push_back
#define Mp make_pair
#define F first
#define S second
#define Sz(x) ll((x).size())
#define all(x) (x).begin(), (x).end()
ll a[maxn], b[maxn];
long long minimum_walk(vector<int> p, int s){
ll n = Sz(p);
for(ll i = 0; i < n; i++){
if(p[i] > i){
for(ll j = i; j < p[i]; j++){
a[j]++;
}
}
else{
for(ll j = i; j > p[i]; j--){
b[j - 1]++;
}
}
}
ll m = n;
while(m && a[m - 1] == m - 1) m--;
ll ans = 0;
for(ll i = 0; i < m - 1; i++){
ans += max(1ll, max(a[i], b[i]));
}
return ans * 2;
}
