// 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: 1.8763744270603266x):
#include <cmath>

#include <cstdio>

#include <cstring>

#include <algorithm>



int read()

{

  int x=0,f=1;

  char ch=getchar();

  while((ch<'0')||(ch>'9'))

    {

      if(ch=='-')

        {

          f=-f;

        }

      ch=getchar();

    }

  while((ch>='0')&&(ch<='9'))

    {

      x=x*10+ch-'0';

      ch=getchar();

    }

  return x*f;

}



const int maxn=200000;

const int maxv=99999999;

const double pi=acos(-1);

const double D=11.4159265358979323846264338328;

const double K=-4.2920367320510338076867830836;



struct point

{

  int x,y;



  bool operator <(const point &other) const

  {

    return x<other.x;

  }

};



int n,a[maxn+10],f[maxn+10],sx,sy,tx,ty;

point p[maxn+10];



int main()

{

  sx=read();

  sy=read();

  tx=read();

  ty=read();

  n=read();

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

    {

      p[i].x=read();

      p[i].y=read();

    }

  if(sx>tx)

    {

      std::swap(sx,tx);

      std::swap(sy,ty);

    }

  if(sy>ty)

    {

      sy=maxv-sy;

      ty=maxv-ty;

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

        {

          p[i].y=maxv-p[i].y;

        }

    }

  std::sort(p+1,p+n+1);

  int tot=0;

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

    {

      if((p[i].x>=sx)&&(p[i].y>=sy)&&(p[i].x<=tx)&&(p[i].y<=ty))

        {

          a[++tot]=p[i].y;

        }

    }

  int cnt=0;

  memset(f,63,sizeof f);

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

    {

      int pos=std::lower_bound(f+1,f+cnt+1,a[i])-f;

      f[pos]=a[i];

      if(pos>cnt)

        {

          ++cnt;

        }

    }

  double ans=100.0*(tx-sx+ty-sy);

  if(cnt==std::min(tx-sx,ty-sy)+1)

    {

      ans+=(cnt-1)*K+D;

    }

  else

    {

      ans+=cnt*K;

    }

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

  return 0;

}