#include "books.h"
#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef vector<ll> vii;
typedef pair<ll,ll> pii;
#define F first
#define S second
#define all(v) v.begin(),v.end()
#define pb push_back
ll n;
bool vis[2000000];
long long minimum_walk(vector<int> p, int s) {
n=p.size();
ll res=0;
bool chk=1;
for(int i=0;i<n;i++) {
if(p[i]!=i)
chk=0;
}
if(chk)
return 0;
ll cnt=0;
for(int i=0;i<n;i++) {
if(p[i]>=i) {
cnt++;
}
vis[p[i]]=1;
if(vis[i])
cnt--;
res+=2*cnt;
if(cnt==0)
res+=2;
}
res-=2;
for(int i=0;i<s;i++) {
if(p[i]==i)
res-=2;
else
break;
}
for(int i=n-1;i>s;i--) {
if(p[i]==i)
res-=2;
else
break;
}
return res;
}
