#pragma GCC optimize("Ofast")
#pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx")
#pragma GCC optimize("unroll-loops")
//#pragma warning(disable : 4996)

#ifdef _MSC_VER
#include <intrin.h>
#define __builtin_popcount __popcnt
#define __builtin_popcountll __popcnt64
#endif

#include <limits.h>
#include <math.h>
#include <time.h>

#include <algorithm>
#include <array>
#include <bitset>
#include <cassert>
#include <complex>
#include <cstdio>
#include <cstring>
#include <functional>
#include <iomanip>
#include <iostream>
#include <iterator>
#include <map>
#include <numeric>
#include <queue>
#include <random>
#include <set>
#include <stack>
#include <string>
#include <unordered_map>
#include <unordered_set>
#include <vector>

using namespace std;

#define REP(i, n) for (int i = 0; i < (n); ++i)
#define REPR(i, n) for (int i = n - 1; i >= 0; --i)
#define FOR(i, m, n) for (int i = m; i < n; ++i)
#define FORR(i, m, n) for (int i = m - 1; i >= n; --i)
#define SORT(v, n) sort(v, v + n);
#define VSORT(v) sort(v.begin(), v.end());
#define REVERSE(v, n) reverse(v, v + n);
#define VREVERSE(v) reverse(v.begin(), v.end())
#define ll long long
#define print(x) cout << (x) << '\n'
#define pe(x) cout << (x) << " "
#define DEBUG(x) cout << #x << ": " << x << endl
#define lb(v, n) lower_bound(v.begin(), v.end(), (n))
#define ub(v, n) upper_bound(v.begin(), v.end(), (n))
#define int long long
#define double long double
#define all(x) (x).begin(), (x).end()
#define print_space(v) REP(i, v.size()) cout << v[i] << ((i == v.size() - 1) ? "\n" : " ")
template <typename T1, typename T2> inline void chmin(T1& a, T2 b) { if (a > b) a = b; }
template <typename T1, typename T2> inline void chmax(T1& a, T2 b) { if (a < b) a = b; }
typedef pair<int, int> pii;
typedef pair<long long, long long> pll;
std::random_device rd;
std::mt19937 mt(rd());
constexpr ll MOD = 1e9 + 7;
constexpr int MAX = 500050;
const double pi = acos(-1);
constexpr double EPS = 1e-8;
constexpr ll LINF = 1e18 + 1;
constexpr int INF = 1e9 + 1;

template< typename T >
size_t longest_increasing_subsequence(const vector< T > &a, bool strict) {
	vector< T > lis;
	for (auto &p : a) {
		typename vector< T >::iterator it;
		if (strict) it = lower_bound(begin(lis), end(lis), p);
		else it = upper_bound(begin(lis), end(lis), p);
		if (end(lis) == it) lis.emplace_back(p);
		else *it = p;
	}
	return lis.size();
}


void solve() {
	int sx, sy, gx, gy;
	cin >> sx >> sy >> gx >> gy;
	int N; cin >> N;
	vector<pii>v;

	REP(i, N) {
		int x, y; cin >> x >> y;
		x -= sx, y -= sy;
		v.push_back({ x,y });
	}
	gx -= sx, gy -= sy;
	sx = 0, sy = 0;
	if (gx < 0 && gy >= 0) {
		gx = -gx;
		REP(i, N)v[i].first = -v[i].first;
	}
	else if (gx < 0 && gy < 0) {
		gx = -gx;
		gy = -gy;
		REP(i, N) { v[i].first = -v[i].first, v[i].second = -v[i].second; }
	}
	else if (gx >= 0 && gy < 0) {
		gy = -gy;
		REP(i, N)v[i].second = -v[i].second;
	}
	assert(gx >= 0 && gy >= 0);
	VSORT(v);
	vector<pii>vxy, vyx;
	REP(i, N) {
		int x = v[i].first, y = v[i].second;
		if (sx <= x && x <= gx && sy <= y && y <= gy) {
			vxy.push_back({ x,y });
			vyx.push_back({ y,x });
		}
	}
	VSORT(vxy);
	VSORT(vyx);
	vector<int>vx, vy;
	for (auto p : vxy)vy.push_back(p.second);
	for (auto p : vyx)vx.push_back(p.second);
	int c = max(longest_increasing_subsequence<int>(vx, true), longest_increasing_subsequence<int>(vy, true));
	//DEBUG(c);
	double res = 100 * (gx + gy);
	assert(c <= min(gx, gy) + 1);
	if (c <= min(gx, gy))res -= (20-pi * 5)*c;
	else {
		res -= (20-pi * 5) * (c - 1);
		res += pi * 10 - 20;
	}
	cout << fixed << setprecision(20) << res << endl;
}


signed main() {
	cin.tie(0);
	ios::sync_with_stdio(false);
	//int q;
	//cin >> q;
	//while (q--)
	solve();
}


Measured memory_bytes: 19436