#include "books.h"
#include <bits/stdc++.h>
#define LL long long
using namespace std;
const LL LINF = 1e18;
int a[10],n;
vector<int>vec;
bool check(){
bool q = 1;
for(int i=0;i<n;i++)
q &= (a[i]==vec[i]);
return q;
}
LL bt(int pos,int cur,int cnt);
LL move(int pos,int cur,int cnt){
LL ret = LINF;
if(pos<n-1)
ret = min(ret,bt(pos+1,cur,cnt+1));
if(pos>0)
ret = min(ret,bt(pos-1,cur,cnt+1));
return ret;
}
LL bt(int pos,int cur,int cnt){
if((cur==-1)&&!pos&&check())
return cnt;
if(cnt>12)
return LINF;
LL ret = LINF;
ret = min(ret,move(pos,cur,cnt));
if(cur==-1){
cur = a[pos];
a[pos] = -1;
ret= min(ret,move(pos,cur,cnt));
a[pos] = cur;
cur = -1;
}
if(a[pos]==-1){
a[pos] = cur;
cur = -1;
ret = min(ret,move(pos,cur,cnt));
cur = a[pos];
a[pos] = -1;
}
if(cur>=0&&a[pos]>=0){
swap(cur,a[pos]);
ret = min(ret,move(pos,cur,cnt));
swap(cur,a[pos]);
}
return ret;
}
long long minimum_walk(std::vector<int> P, int s) {
vec = P;
n = P.size();
for(int i=0;i<n;i++)
a[i] = i;
return bt(0,-1,0);
}
