#include<bits/stdc++.h>
#define sqr(x) ((x)*(x))
#define ll long long
#define ull unsigned long long
#define ui unsigned int
#define ld long double
#define vi vector<int>
#define HEAP(...) priority_queue<__VA_ARGS__ >
#define heap(...) priority_queue<__VA_ARGS__,vector<__VA_ARGS__ >,greater<__VA_ARGS__ > > 
#define pii pair<int,int> 
#define pb push_back
#define mp make_pair
#define debuge cerr<<"isok"<<endl
#define debug(x) cerr<<#x<<"="<<x<<endl
#define dprintf(...) fprintf(stderr,__VA_ARGS__)
#define SS second
#define FF first
#define ls (k<<1)
#define rs (k<<1|1)
#define clr(a,x) memset(a,x,sizeof(a))
#define cpy(a,x) memcpy(a,x,sizeof(a))
#define file(x) freopen(x".in","r",stdin),freopen(x".out","w",stdout)
#define SZ(x) ((int)x.size())
using namespace std;
template<class T> inline void gmin(T &x,const T &y){if(x>y) x=y;}
template<class T> inline void gmax(T &x,const T &y){if(x<y) x=y;}
const int BufferSize=1<<16;
char buffer[BufferSize],*Bufferhead,*Buffertail;
bool Terminal;
inline char Getchar(){
	if(Bufferhead==Buffertail){
		int l=fread(buffer,1,BufferSize,stdin);
		if(!l){Terminal=1;return 0;}
		Buffertail=(Bufferhead=buffer)+l;
	}
	return *Bufferhead++;
}
template<class T>inline bool read(T &x){
	x=0;char c=Getchar(),rev=0;
	while(c<'0'||c>'9'){c=Getchar();rev|=c=='-';if(Terminal)return 0;}
	while(c>='0'&&c<='9') x=x*10+c-'0',c=Getchar();
	if(c=='.'){
		c=Getchar();double t=0.1;
		while(c>='0'&&c<='9') x=x+(c-'0')*t,c=Getchar(),t=t/10;
	}
	x=rev?-x:x;
	return 1;
}
inline bool reads(char *x){
	char c=Getchar();
	while(c<33||c>126){c=Getchar();if(Terminal)return 0;}
	while(c>=33&&c<=126) (*x++)=c,c=Getchar();
	*x=0;return 1;
}
template<class T>inline void print(T x,const char c='\n'){
	if(!x){putchar('0');putchar(c);return;}
	if(x<0) putchar('-'),x=-x;
	int m=0,a[20];
	while(x) a[m++]=x%10,x/=10;
	while(m--) putchar(a[m]+'0');
	putchar(c);
}
//--------------------------------head---------------------------------------------

const ld pi=acos(-1);
const ld len1=10.0*pi-20,len2=20.0-5.0*pi;
const int inf=0x3f3f3f3f,bnd=1e8+5;
const int N=200005,M=100005,mod=1e9+7;
template<class T,class S> inline void ch(T &x,const S y){x=(x+y)%mod;}
inline int exp(int x,int y,const int mod=::mod){
	int ans=1;
	while(y){
		if(y&1) ans=(ll)ans*x%mod;
		x=(ll)x*x%mod;y>>=1;
	}return ans;
}

int n,x1,yy1,x2,y2,dp[N],c[N],yy[N];
struct node{int x,y;}p[N];
inline bool operator ==(node a,node b){return a.x==b.x&&a.y==b.y;}
inline bool cmp(node a,node b){return mp(a.x,a.y)<mp(b.x,b.y);}
inline void add(int x,int y){while(x<=n) gmax(c[x],y),x+=x&-x;}
inline int get(int x){
	int ans=-inf;
	while(x) gmax(ans,c[x]),x-=x&-x;
	return ans;
}

bool con(int l,int r,int x){
	if(l>r) swap(l,r);
	return l<=x&&x<=r;
}

int main(){
#ifdef rqgao2014
	freopen("input.txt","r",stdin);
#endif
	scanf("%d%d%d%d",&x1,&yy1,&x2,&y2);
	scanf("%d",&n);
	for(int i=1;i<=n;i++)
		scanf("%d%d",&p[i].x,&p[i].y);
	if(x1>x2) swap(x1,x2),swap(yy1,y2);
	if(yy1>y2){
		yy1=bnd-yy1;y2=bnd-y2;
		for(int i=1;i<=n;i++)
			p[i].y=bnd-p[i].y;
	}
	if(x1==x2){
		ld isok=0;
		for(int i=1;i<=n;i++)
			if(p[i].x==x1&&con(yy1,y2,p[i].y)) isok=1;
		printf("%.15Lf\n",(ld)(y2-yy1)*100.0+len1*isok);
		return 0;
	}
	if(yy1==y2){
		ld isok=0;
		for(int i=1;i<=n;i++)
			if(p[i].y==yy1&&con(x1,x2,p[i].x)) isok=1;
		printf("%.15Lf\n",(ld)(x2-x1)*100.0+len1*isok);
		return 0;
	}
	p[++n]=(node){x1,yy1};
	p[++n]=(node){x2,y2};
	for(int i=1;i<=n;i++)
		yy[i]=p[i].y;
	sort(yy+1,yy+n+1);
	sort(p+1,p+n+1,cmp);
	for(int i=1;i<=n;i++) c[i]=-inf;
	int ans=0.0;
	for(int i=1;i<=n;i++){
		if(p[i]==(node){x1,yy1}) dp[i]=0; else dp[i]=-inf;
		int k=lower_bound(yy+1,yy+n+1,p[i].y)-yy;
		gmax(dp[i],get(k)+1);
		add(k,dp[i]);
		if(p[i]==(node){x2,y2}) ans=dp[i]-1;
	}
//	debug(ans);
	int m=min(x2-x1,y2-yy1);
	if(ans==m+1){
		printf("%.15Lf\n",(ld)(x2+y2-x1-yy1)*100.0-(ans-1)*len2+len1);
	} 
	else printf("%.15Lf\n",(ld)(x2+y2-x1-yy1)*100.0-ans*len2);
	return 0;
}

Measured memory_bytes: 4224