#include <bits/stdc++.h>
using namespace std;

using ll=long long;
#define int ll

#define rng(i,a,b) for(int i=int(a);i<int(b);i++)
#define rep(i,b) rng(i,0,b)
#define gnr(i,a,b) for(int i=int(b)-1;i>=int(a);i--)
#define per(i,b) gnr(i,0,b)
#define pb push_back
#define eb emplace_back
#define a first
#define b second
#define bg begin()
#define ed end()
#define all(x) x.bg,x.ed
#ifdef LOCAL
#define dmp(x) cerr<<__LINE__<<" "<<#x<<" "<<x<<endl
#else
#define dmp(x) void(0)
#endif

template<class t,class u> void chmax(t&a,u b){if(a<b)a=b;}
template<class t,class u> void chmin(t&a,u b){if(b<a)a=b;}

template<class t> using vc=vector<t>;
template<class t> using vvc=vc<vc<t>>;

using pi=pair<int,int>;
using vi=vc<int>;

template<class t,class u>
ostream& operator<<(ostream& os,const pair<t,u>& p){
	return os<<"{"<<p.a<<","<<p.b<<"}";
}

template<class t> ostream& operator<<(ostream& os,const vc<t>& v){
	os<<"{";
	for(auto e:v)os<<e<<",";
	return os<<"}";
}

#define mp make_pair
#define mt make_tuple
#define one(x) memset(x,-1,sizeof(x))
#define zero(x) memset(x,0,sizeof(x))
#ifdef LOCAL
void dmpr(ostream&os){os<<endl;}
template<class T,class... Args>
void dmpr(ostream&os,const T&t,const Args&... args){
	os<<t<<" ";
	dmpr(os,args...);
}
#define dmp2(...) dmpr(cerr,"Line:",__LINE__,##__VA_ARGS__)
#else
#define dmp2(...) void(0)
#endif

using uint=unsigned;
using ull=unsigned long long;

template<int i,class T>
void print_tuple(ostream&,const T&){
}

template<int i,class T,class H,class ...Args>
void print_tuple(ostream&os,const T&t){
	if(i)os<<",";
	os<<get<i>(t);
	print_tuple<i+1,T,Args...>(os,t);
}

template<class ...Args>
ostream& operator<<(ostream&os,const tuple<Args...>&t){
	os<<"{";
	print_tuple<0,tuple<Args...>,Args...>(os,t);
	return os<<"}";
}

void print(ll x,int suc=1){
	cout<<x;
	if(suc==1)
		cout<<"\n";
	if(suc==2)
		cout<<" ";
}

ll read(){
	ll i;
	cin>>i;
	return i;
}

vi readvi(int n,int off=0){
	vi v(n);
	rep(i,n)v[i]=read()+off;
	return v;
}

template<class T>
void print(const vector<T>&v,int suc=1){
	rep(i,v.size())
		print(v[i],i==int(v.size())-1?suc:2);
}

string readString(){
	string s;
	cin>>s;
	return s;
}

template<class T>
T sq(const T& t){
	return t*t;
}

//#define CAPITAL
void yes(bool ex=true){
	#ifdef CAPITAL
	cout<<"YES"<<endl;
	#else
	cout<<"Yes"<<endl;
	#endif
	if(ex)exit(0);
}
void no(bool ex=true){
	#ifdef CAPITAL
	cout<<"NO"<<endl;
	#else
	cout<<"No"<<endl;
	#endif
	if(ex)exit(0);
}

constexpr ll ten(int n){
	return n==0?1:ten(n-1)*10;
}

const ll infLL=LLONG_MAX/3;

#ifdef int
const int inf=infLL;
#else
const int inf=INT_MAX/2-100;
#endif

int topbit(signed t){
	return t==0?-1:31-__builtin_clz(t);
}
int topbit(ll t){
	return t==0?-1:63-__builtin_clzll(t);
}
int botbit(signed a){
	return a==0?32:__builtin_ctz(a);
}
int botbit(ll a){
	return a==0?64:__builtin_ctzll(a);
}
int popcount(signed t){
	return __builtin_popcount(t);
}
int popcount(ll t){
	return __builtin_popcountll(t);
}
bool ispow2(int i){
	return i&&(i&-i)==i;
}
int mask(int i){
	return (int(1)<<i)-1;
}

bool inc(int a,int b,int c){
	return a<=b&&b<=c;
}

template<class t> void mkuni(vc<t>&v){
	sort(all(v));
	v.erase(unique(all(v)),v.ed);
}

ll rand_int(ll l, ll r) { //[l, r]
	#ifdef LOCAL
	static mt19937_64 gen;
	#else
    static random_device rd;
    static mt19937_64 gen(rd());
    #endif
    return uniform_int_distribution<ll>(l, r)(gen);
}

template<class t>
int lwb(const vc<t>&v,const t&a){
	return lower_bound(all(v),a)-v.bg;
}

//CF Global3 H
//point update
template<class T,class F>
struct SegTree{
	vc<T> buf;
	int s;
	const F f;
	const T g;
	SegTree(const vc<T>& d,F ff,T gg):f(ff),g(gg){
		int n=d.size();
		s=1;
		while(s<n)s*=2;
		buf.resize(s*2,g);
		rep(i,n)
			buf[i+s]=d[i];
		gnr(i,1,s)
			u(i);
	}
	void u(int i){
		buf[i]=f(buf[i*2],buf[i*2+1]);
	}
	void set(int i,T t){
		i+=s;
		buf[i]=t;
		while(i>>=1)u(i);
	}
	void upd(int i,T t){
		i+=s;
		buf[i]=f(buf[i],t);
		while(i>>=1)u(i);
	}
	T get(int b,int e,int l,int r,int i){
		if(e<=l||r<=b)return g;
		if(b<=l&&r<=e)return buf[i];
		int m=(l+r)/2;
		return f(get(b,e,l,m,i*2),get(b,e,m,r,i*2+1));
	}
	T get(int b,int e){
		return get(b,e,0,s,1);
	}
};
template<class T,class F>
SegTree<T,F> segtree(const vc<T>& d,F f,T g){
	return SegTree<T,F>(d,f,g);
}

signed main(){
	cin.tie(0);
	ios::sync_with_stdio(0);
	cout<<fixed<<setprecision(20);
	
	int n,q,a,b;cin>>n>>q>>a>>b;
	vi x=readvi(q);
	
	vi vs=x;
	vs.pb(a);
	vs.pb(b);
	mkuni(vs);
	int s=vs.size();
	
	auto imin=[&](int i,int j){return min(i,j);};
	auto l=segtree(vi(s,inf),imin,inf);
	auto r=segtree(vi(s,inf),imin,inf);
	
	a=lwb(vs,a);
	b=lwb(vs,b);
	
	int pre=a;
	l.upd(b,0-vs[b]);
	r.upd(b,vs[b]);
	
	int off=0;
	int last=0;
	for(auto v:x){
		int i=lwb(vs,v);
		
		int w=min(vs[i]+l.get(0,i),-vs[i]+r.get(i,s))+off;
		
		off+=abs(vs[pre]-vs[i]);
		last+=abs(vs[pre]-vs[i]);
		l.upd(pre,w-vs[pre]-off);
		r.upd(pre,w+vs[pre]-off);
		
		chmin(last,w);
		
		pre=i;
	}
	
	cout<<last<<endl;
}


Measured memory_bytes: 9700