#include <bits/stdc++.h>
                                        #include<iostream>
                                        #include<cstdio>
                                        #include<vector>
                                        #include<queue>
                                        #include<map>
                                        #include<cstring>
                                        #include<string>
                                        #include <math.h>
                                        #include<algorithm>
                                    //    #include <boost/multiprecision/cpp_int.hpp>
                                        #include<functional>
                               #define int long long
                                        #define inf  1000000007
                                        #define pa pair<int,int>
                                        #define ll long long
                                        #define pal pair<double,double>
                                        #define ppap pair<pa,int>
                                  
                                        #define ssa pair<string,int>
                                        #define  mp make_pair
                                        #define  pb push_back
                                        #define EPS (1e-7)
                                        #define equals(a,b) (fabs((a)-(b))<EPS)
int dx[4]={0,-1,0,1};
int dy[4]={1,0,-1,0};
                                        using namespace std;
                               			class pa3{
                                        	public:
                                        	int x,y,z;
                                        	pa3(int x=0,int y=0,int z=0):x(x),y(y),z(z) {}
                                        	bool operator < (const pa3 &p) const{
                                        		if(x!=p.x) return x<p.x;
                                        		if(y!=p.y) return y<p.y;
                                        		 return z<p.z;
                                        		//return x != p.x ? x<p.x: y<p.y;
                                        	}
                               				bool operator > (const pa3 &p) const{
                                        		if(x!=p.x) return x>p.x;
                                        		if(y!=p.y) return y>p.y;
                                        		 return z>p.z;
                                        		//return x != p.x ? x<p.x: y<p.y;
                                        	}
                                        	bool operator == (const pa3 &p) const{
                                        		return x==p.x && y==p.y && z==p.z;
                                        	}
                                        		bool operator != (const pa3 &p) const{
                                        			return !( x==p.x && y==p.y && z==p.z);
                                        	}
                                        
                                        };
                                        
                                        class pa4{
                                        	public:
                                        	int x;
                                        	int y,z,w;
                                        	pa4(int x=0,int y=0,int z=0,int w=0):x(x),y(y),z(z),w(w) {}
                                        	bool operator < (const pa4 &p) const{
                                        		if(x!=p.x) return x<p.x;
                                        		if(y!=p.y) return y<p.y;
                                        		if(z!=p.z)return z<p.z;
                                        		return w<p.w;
                                        		//return x != p.x ? x<p.x: y<p.y;
                                        	}
                                        	bool operator > (const pa4 &p) const{
                                        		if(x!=p.x) return x>p.x;
                                        		if(y!=p.y) return y>p.y;
                                        		if(z!=p.z)return z>p.z;
                                        		return w>p.w;
                                        		//return x != p.x ? x<p.x: y<p.y;
                                        	}
                                        	bool operator == (const pa4 &p) const{
                                        		return x==p.x && y==p.y && z==p.z &&w==p.w;
                                        	}
                                        		
                                        
                                        };
                                        class pa5{
                                        	public:
                                        	int x0, x1,x2,x3,x4;
                                        	
                                        	
                                        	bool operator > (const pa5 &p) const{
                                        		if(x0!=p.x0) return x0<p.x0;
                                        		
                                        		return x1+x2+x3+x4>p.x4+p.x3+p.x2+p.x1;
                                        		//return x != p.x ? x<p.x: y<p.y;
                                        	}
                                        	
                                        	bool operator < (const pa5 &p) const{
                                        		if(x0!=p.x0) return x0>p.x0;
                                        		
                                        		return x1+x2+x3+x4<p.x4+p.x3+p.x2+p.x1;
                                        		//return x != p.x ? x<p.x: y<p.y;
                                        	}
                                        	bool operator == (const pa5 &p) const{
                                        		return x0==p.x0 && x1==p.x1 && x2==p.x2 &&x3==p.x3 && x4==p.x4;
                                        	}
                                        		
                                        
                                        };
                                        class pa2{
                                        	public:
                                        	int x,y;
                                        	pa2(int x=0,int y=0):x(x),y(y) {}
                                        	pa2 operator + (pa2 p) {return pa2(x+p.x,y+p.y);}
                                        	pa2 operator - (pa2 p) {return pa2(x-p.x,y-p.y);}
                                        	bool operator < (const pa2 &p) const{
                                        		return x != p.x ? x<p.x: y<p.y;
                                        	}
                                        	bool operator > (const pa2 &p) const{
                                        		return x != p.x ? x>p.x: y>p.y;
                                        	}
                                        	bool operator == (const pa2 &p) const{
                                        		return abs(x-p.x)==0 && abs(y-p.y)==0;
                                        	}
                                        	bool operator != (const pa2 &p) const{
                                        		return !(abs(x-p.x)==0 && abs(y-p.y)==0);
                                        	}
                                        		
                                        
                                        };
                                        
                                               #define ppa pair<int,pas>
                                        class Point{
                                        	public:
                                        	double x,y;
                                        	Point(double x=0,double y=0):x(x),y(y) {}
                                        	Point operator + (Point p) {return Point(x+p.x,y+p.y);}
                                        	Point operator - (Point p) {return Point(x-p.x,y-p.y);}
                                        	Point operator * (double a) {return Point(x*a,y*a);}
                                        	Point operator / (double a) {return Point(x/a,y/a);}
                                        	double absv() {return sqrt(norm());}
                                        	double norm() {return x*x+y*y;}
                                        	bool operator < (const Point &p) const{
                                        		return x != p.x ? x<p.x: y<p.y;
                                        	}
                                        	bool operator == (const Point &p) const{
                                        		return fabs(x-p.x)<EPS && fabs(y-p.y)<EPS;
                                        	}
                                        };
                                        typedef Point Vector;
                                 #define pl pair<int,pas>
                                        struct Segment{
                                        Point p1,p2;
                                        };
                                         double dot(Vector a,Vector b){
                                        	return a.x*b.x+a.y*b.y;
                                        }
                                        double cross(Vector a,Vector b){
                                        	return a.x*b.y-a.y*b.x;
                                        }
                                    
            bool parareru(Point a,Point b,Point c,Point d){
            //	if(abs(cross(a-b,d-c))<EPS)cout<<"dd "<<cross(a-b,d-c)<<endl;
            	return abs(cross(a-b,d-c))<EPS;
            }
            double distance_ls_p(Point a, Point b, Point c) {
              if ( dot(b-a, c-a) < EPS ) return (c-a).absv();
              if ( dot(a-b, c-b) < EPS ) return (c-b).absv();
              return abs(cross(b-a, c-a)) / (b-a).absv();
            }
            bool is_intersected_ls(Segment a,Segment b) {
            	if(a.p1==b.p1||a.p2==b.p1||a.p1==b.p2||a.p2==b.p2) return false;
            	if(parareru((a.p2),(a.p1),(a.p1),(b.p2))&&parareru((a.p2),(a.p1),(a.p1),(b.p1))){
            //		cout<<"sss"<<endl;
            		if(dot(a.p1-b.p1,a.p1-b.p2)<EPS) return true;
            		if(dot(a.p2-b.p1,a.p2-b.p2)<EPS) return true;
            		if(dot(a.p1-b.p1,a.p2-b.p1)<EPS) return true;
            		if(dot(a.p1-b.p2,a.p2-b.p2)<EPS) return true;
            		return false;
            	}
              else return ( cross(a.p2-a.p1, b.p1-a.p1) * cross(a.p2-a.p1, b.p2-a.p1) < EPS ) && ( cross(b.p2-b.p1, a.p1-b.p1) * cross(b.p2-b.p1, a.p2-b.p1) < EPS );
            }
             
            double segment_dis(Segment a,Segment b){
            	if(is_intersected_ls(a,b))return 0;
            	double r=distance_ls_p(a.p1, a.p2, b.p1);
            	r=min(r,distance_ls_p(a.p1, a.p2, b.p2));
            	r=min(r,distance_ls_p(b.p1, b.p2, a.p2));
            	r=min(r,distance_ls_p(b.p1, b.p2, a.p1));
            	return r;
            }
            Point intersection_ls(Segment a, Segment b) {
              Point ba = b.p2-b.p1;
              double d1 = abs(cross(ba, a.p1-b.p1));
              double d2 = abs(cross(ba, a.p2-b.p1));
              double t = d1 / (d1 + d2);
             
              return a.p1 + (a.p2-a.p1) * t;
            }
             
                            string itos( int i ) {
                            ostringstream s ;
                            s << i ;
                            return s.str() ;
                            }
                             
                            int gcd(int v,int b){
                            	if(v>b) return gcd(b,v);
                            	if(v==b) return b;
                            	if(b%v==0) return v;
                            	return gcd(v,b%v);
                            }
             
                            double distans(double x1,double y1,double x2,double y2){
                            	double rr=(x1-x2)*(x1-x2)+(y1-y2)*(y1-y2);
                            	return sqrt(rr);
                            	
                            }
                            
   //         int pr[2000010];
     //       int inv[2000010];
            
            int beki(int wa,int rr,int warukazu){
            	if(rr==0) return 1ll;
            	if(rr==1) return wa%warukazu;
            	if(rr%2==1) return (beki(wa,rr-1,warukazu)*wa)%warukazu;
            	int zx=beki(wa,rr/2,warukazu);
            	return (zx*zx)%warukazu;
            }
            /*
			int comb(int nn,int rr){
				int r=pr[nn]*inv[rr];
				r%=inf;
				r*=inv[nn-rr];
				r%=inf;
				return r;
			}
            
            void gya(int ert){
            	pr[0]=1;
            	for(int i=1;i<ert;i++){
            		pr[i]=(pr[i-1]*i)%inf;
            	}
            	for(int i=0;i<ert;i++) inv[i]=beki(pr[i],inf-2,inf);
            	
            }
             */
			//priority_queue<pa3,vector<pa3>,greater<pa3>> pq;            
             //sort(ve.begin(),ve.end(),greater<int>());
                                     //----------------kokomade tenpure------------
unsigned int randxor()
{
    static unsigned int x=123456789,y=362436069,z=521288629,w=88675123;
    unsigned int t;
    t=(x^(x<<11));x=y;y=z;z=w; return( w=(w^(w>>19))^(t^(t>>8)) );
}
int inff=1000000000000000ll;
struct Segmin{
	//       1
	//   2        3
	// 4   5   6    7
	
	
	private:
	public:
	
	// (1<<15)=32768
	// 1<<16 = 65536
	// 1<<17 = 131072
	// 1<<18 = 262144
	
	int cor=(1<<18);
	
	vector<pa> vec;
	
	void shoki1(){
		
		vec.resize(2*cor+3, mp(0,0));
		for(int i=cor;i<2*cor;i++)vec[i].second=i-cor;
	}
		void shoki2(){
			for(int i=cor-1;i>0;i--) {
				if(vec[2*i].first<=vec[2*i+1].first) vec[i]=vec[2*i];
				else vec[i]=vec[2*i+1];
			}
		}
		
	void updadd(int x,int w){
		//x 項目に w加算
		x+=cor;
		vec[x].first+=w;
		while(1){
			x/=2;
			if(x==0) break;
			if(vec[2*x].first<=vec[2*x+1].first) vec[x]=vec[2*x];
			else vec[x]=vec[2*x+1];
		}
		
	}
	
	void updchan(int x,int w){
		//x項目をwに変更
		x+=cor;
		vec[x].first=w;
		while(1){
			x/=2;
			if(x==0) break;
			if(vec[2*x].first<=vec[2*x+1].first) vec[x]=vec[2*x];
			else vec[x]=vec[2*x+1];
		}
		
	}
	// [a,b)
	// k-th node
	// k no kukanha [l,r)
	pa segmin(int a,int b,int k=1,int l=0,int r=-10){
		if(r<0)r=cor;
		
	//	cout<<a<<" "<<b<<" "<<k<<" "<<l<<" "<<r<<endl;
		
		if(a<=l && r<=b){
			return vec[k];
		}
		if(r<=a || b<=l){
			return mp(3ll*inff,-1);
		}
		
		pa v1=segmin(a,b,k*2,l,(l+r)/2),v2=segmin(a,b,k*2+1,(l+r)/2,r);
		
		if(v1.first<=v2.first)return v1;
		else return v2;
	}
	
}; 
int jou=200000;

Segmin a0,a1,b0,b1;
vector<int> ve;
  signed main(){
  	              cin.tie(0);
    		ios::sync_with_stdio(false);

  	a0.shoki1();
  	a1.shoki1();
  	b0.shoki1();
  	b1.shoki1();
  	
  	for(int i=1;i<=jou;i++){
  		a0.vec[i+a0.cor].first=inff+i;
  		b0.vec[i+a0.cor].first=inff+i;
  		b1.vec[i+a0.cor].first=inff-i;
  		a1.vec[i+a0.cor].first=inff-i;
  	}
  	
  	a0.shoki2();
  	a1.shoki2();
  	b0.shoki2();
  	b1.shoki2();
  //	cout<<inff<<endl;
  	//cout<<a0.segmin(1,2).second<<endl;
  	int n,q,a,b;
  	cin>>n>>q>>a>>b;
  	int x;
  	cin>>x;
  	ve.pb(x);
  	a0.updchan(b,abs(a-x)+b);
  	a1.updchan(b,abs(a-x)-b);
  	b0.updchan(a,abs(b-x)+a);
  	b1.updchan(a,abs(b-x)-a);
  	int da=0,db=0;
  	/*
  	for(int i=1;i<=n;i++){
  			cout<<a0.segmin(i,i+1).first+da-i<<" ";
  		}
  		cout<<endl;
  		
  		for(int i=1;i<=n;i++){
  			cout<<a1.segmin(i,i+1).first+da+i<<" ";
  		}
  		cout<<endl;
  		
  		for(int i=1;i<=n;i++){
  			cout<<b0.segmin(i,i+1).first+db-i<<" ";
  		}
  		cout<<endl;
  		
  		for(int i=1;i<=n;i++){
  			cout<<b1.segmin(i,i+1).first+db+i<<" ";
  		}
  		cout<<endl;
  	*/
  	for(int i=1;i<q;i++){
  		cin>>x;
  		ve.pb(x);
  		int al=x+db+b1.segmin(1,x+1).first;
  		int ar=-x+db+b0.segmin(x,jou+1).first;
  		
  		int bl=x+da+a1.segmin(1,x+1).first;
  		int br=-x+da+a0.segmin(x,jou+1).first;
  		
  		
  		da+=abs(ve[i-1]-ve[i]);
  		db+=abs(ve[i-1]-ve[i]);
  		int maeb=b0.segmin(ve[i-1],ve[i-1]+1).first-ve[i-1]+db;
  			
  		int maea=a0.segmin(ve[i-1],ve[i-1]+1).first-ve[i-1]+da;
  			maeb=min({maeb,bl,br});
  		maea=min({maea,al,ar});
  		//cout<<x<<" "<<al<<" "<<ar<<"  "<<bl<<" xxx "<<a1.segmin(x,jou+1).first<<"  "<<br<<endl;
  		a0.updchan(ve[i-1],maea+ve[i-1]-da);
  		a1.updchan(ve[i-1],maea-ve[i-1]-da);
  		b0.updchan(ve[i-1],maeb+ve[i-1]-db);
  		b1.updchan(ve[i-1],maeb-ve[i-1]-db);
  		/*
  		for(int i=1;i<=n;i++){
  			cout<<a0.segmin(i,i+1).first+da-i<<" ";
  		}
  		cout<<endl;
  		
  		for(int i=1;i<=n;i++){
  			cout<<a1.segmin(i,i+1).first+da+i<<" ";
  		}
  		cout<<endl;
  		
  		for(int i=1;i<=n;i++){
  			cout<<b0.segmin(i,i+1).first+db-i<<" ";
  		}
  		cout<<endl;
  		
  		for(int i=1;i<=n;i++){
  			cout<<b1.segmin(i,i+1).first+db+i<<" ";
  		}
  		cout<<endl;
  		*/
  	}
  	
  	int ans=inff;
  	
  	for(int i=1;i<=jou;i++){
  		ans=min(ans,a0.segmin(i,i+1).first-i+da);
  		ans=min(ans,a1.segmin(i,i+1).first+i+da);
  		ans=min(ans,b0.segmin(i,i+1).first-i+db);
  		ans=min(ans,b1.segmin(i,i+1).first+i+db);
  	}
  	cout<<ans<<endl;
  	
  	return 0;
                }
                


Measured memory_bytes: 36720