// Slower C++ solution:
#include<bits/stdc++.h>

#define F(i,a,b) for(int i=a;i<=(b);++i)

#define F2(i,a,b) for(int i=a;i<(b);++i)

#define dF(i,a,b) for(int i=a;i>=(b);--i)

#define dF2(i,a,b) for(int i=a;i>(b);--i)

#define eF(i,u) for(int i=h[u];i;i=nxt[i])

#define ll long long

#define ld double

using namespace std;



ll Sx,Sy,Tx,Ty;

ll ansi,ansp=0;

int n,cnt,P[200001],Ans;

ll x[200001],y[200001];

ll X[200001],Y[200001],tmp[200001];

ll t[200001];

inline bool cmp(int p1,int p2){return X[p1]<X[p2];}



inline int BS(ll k){

	int l=0,r=cnt,mid,ans;

	while(l<=r){

		mid=l+r>>1;

		if(tmp[mid]>k) ans=mid, l=mid+1;

		else r=mid-1;

	}

	return ans;

}



int main(){

	scanf("%lld%lld%lld%lld",&Sx,&Sy,&Tx,&Ty);

	ansi=abs(Sx-Tx)+abs(Sy-Ty); ansi*=10;

	scanf("%d",&n);

	F(i,1,n) scanf("%lld%lld",x+i,y+i);

	if(Sx==Tx){

		if(Sy>Ty) swap(Sy,Ty);

		F(i,1,n) if(x[i]==Sx&&Sy<y[i]&&y[i]<Ty) ansi-=2, ansp+=10;

		printf("%.15lf",10.*ansi+acos(-1)*ansp); return 0;

	}

	if(Sy==Ty){

		if(Sx>Tx) swap(Sx,Tx);

		F(i,1,n) if(y[i]==Sy&&Sx<x[i]&&x[i]<Tx) ansi-=2, ansp+=10;

		printf("%.15lf",10.*ansi+acos(-1)*ansp); return 0;

	}

	if(Sx>Tx) swap(Sx,Tx), swap(Sy,Ty);

	if(Sy<Ty)

		F(i,1,n) if(Sx<=x[i]&&x[i]<=Tx&&Sy<=y[i]&&y[i]<=Ty) X[++cnt]=x[i], Y[cnt]=y[i], P[cnt]=cnt;

	if(Sy>Ty)

		F(i,1,n) if(Sx<=x[i]&&x[i]<=Tx&&Ty<=y[i]&&y[i]<=Sy) X[++cnt]=x[i], Y[cnt]=y[i], P[cnt]=cnt;

	F(i,1,cnt) t[i]=Y[i];

	sort(t+1,t+cnt+1);

	F(i,1,cnt) Y[i]=lower_bound(t+1,t+cnt+1,Y[i])-t;

	sort(P+1,P+cnt+1,cmp);

	if(Sy<Ty){

		memset(tmp,0x3f,sizeof tmp);

		tmp[0]=0;

		F(i,1,cnt){

			int k=lower_bound(tmp,tmp+cnt+1,Y[P[i]])-tmp;

			tmp[k]=min(tmp[k],Y[P[i]]);

			Ans=max(Ans,k);

		}

		if(Ans==min(abs(Sx-Tx),abs(Sy-Ty))+1) printf("%.15lf",10.*(ansi-2*Ans)+acos(-1)*5*Ans+5*acos(-1));

		else printf("%.15lf",10.*(ansi-2*Ans)+acos(-1)*5*Ans);

	}

	else{

		tmp[0]=0x3f3f3f3f;

		F(i,1,cnt){

			int k=BS(Y[P[i]]);

			tmp[k+1]=max(tmp[k+1],Y[P[i]]);

			Ans=max(Ans,k+1);

		}

		if(Ans==min(abs(Sx-Tx),abs(Sy-Ty))+1) printf("%.15lf",10.*(ansi-2*Ans)+acos(-1)*5*Ans+5*acos(-1));

		else printf("%.15lf",10.*(ansi-2*Ans)+acos(-1)*5*Ans);

	}

	return 0;

}

// Faster C++ solution for the same problem (measured speedup: 9.383065967207148x):
#include<cstdio>

#include<cstring>

#include<algorithm>

#define MAXN 200000

using namespace std;

struct Point

{

	int x,y;

	Point(){};

	Point(int _x,int _y):x(_x),y(_y){};

}ft[MAXN+5],P1,P2;

int N;

int B[MAXN+5];

bool cmp1(const Point &a,const Point &b)

{return a.x<b.x;}

bool cmp2(const Point &a,const Point &b)

{return a.x>b.x;}

int main()

{

	scanf("%d %d %d %d",&P1.x,&P1.y,&P2.x,&P2.y);

	if(P1.x>P2.x)

		swap(P1,P2);

	double ans=0;

	if(P1.y<P2.y)

	{

		scanf("%d",&N);

		for(int i=1;i<=N;i++)

		{

			scanf("%d %d",&ft[i].x,&ft[i].y);

			if(ft[i].x<P1.x||ft[i].y<P1.y||ft[i].x>P2.x||ft[i].y>P2.y)

			{

				i--,N--;

				continue;

			}

		}

		sort(ft+1,ft+1+N,cmp1);

	}

	else if(P1.y>=P2.y)

	{

		scanf("%d",&N);

		for(int i=1;i<=N;i++)

		{

			scanf("%d %d",&ft[i].x,&ft[i].y);

			if(ft[i].x<P1.x||ft[i].y>P1.y||ft[i].x>P2.x||ft[i].y<P2.y)

			{

				i--,N--;

				continue;

			}

		}

		sort(ft+1,ft+1+N,cmp2);

	}

	if(N==0)

		ans=(1.0*abs(P1.x-P2.x)+1.0*abs(P1.y-P2.y))*100.0;

	else

	{

		int maxl=1;

		B[1]=ft[1].y;

		for(int i=1;i<=N;i++)

		{

			int p=lower_bound(B+1,B+1+maxl,ft[i].y)-B;

			B[p]=ft[i].y;

			maxl=max(maxl,p);

		}

		int lim=min(abs(P1.x-P2.x),abs(P1.y-P2.y));

		int rl=min(maxl,lim);

		double del=-4.2920367320510338;

		double add=11.41592653589793238;

		ans=(1.0*abs(P1.x-P2.x)+1.0*abs(P1.y-P2.y))*100.0+1.0*rl*del;

		if(maxl>lim)

			ans+=(1.0*maxl-1.0*lim)*add;

 	}

	printf("%.15f\n",ans);

	return 0;

}