#include <bits/stdc++.h>
using namespace std;
#define modulo 1000000007
#define mod(mod_x) ((((long long)mod_x+modulo))%modulo)
#define Inf 10000000000000000




int main(){
	
	int x1,x2,y1,y2;
	cin>>x1>>y1>>x2>>y2;
	
	int N;
	cin>>N;
	
	vector<int> X(N),Y(N);
	
	for(int i=0;i<N;i++){
		cin>>X[i]>>Y[i];
	}
	
	if(x1>x2){
		for(int i=0;i<N;i++){
			X[i] += (x1-X[i])*2;
		}
		x2 += (x1-x2)*2;
	}
	
	if(y1>y2){
		for(int i=0;i<N;i++){
			Y[i] += (y1-Y[i])*2;
		}
		y2 += (y1-y2)*2;
	}
	
	vector<pair<long long,long long>> P;
	for(int i=0;i<N;i++){
		if(X[i]>=x1&&X[i]<=x2&&Y[i]>=y1&&Y[i]<=y2){
			P.emplace_back(X[i],Y[i]);
		}
	}
	
	sort(P.begin(),P.end());
	
	vector<long long> V(N+1,Inf);
	V[0] = -Inf;
	
	for(int i=0;i<P.size();i++){
		long long y = P[i].second;
		int ok = 0;
		int ng = N+1;
		while(ng-ok>1){
			int mid = (ok+ng)/2;
			if(V[mid]<y)ok=mid;
			else ng=mid;
		}
		V[ok+1] = min(V[ok+1],y);
	}
	int cnt = 0;
	for(int i=0;i<V.size();i++){
		if(V[i]!=Inf){
			cnt = i;
		}
	}
	
	double ans = 0.0;
	double PI = acos(-1);
	ans += 100.0*((x2-x1)+(y2-y1));
	ans -= cnt * 20.0;
	ans += PI * 5 * cnt;
	if(cnt == y2-y1+1||cnt==x2-x1+1){
		ans += PI * 5;
	}
	
	cout<<fixed<<setprecision(20)<<ans<<endl;
	
	
	return 0;
}