#include "bits/stdc++.h"

using namespace std;
#ifdef _DEBUG
#define _GLIBCXX_DEBUG
#include "dump.hpp"
#else
#define dump(...)
#endif

#define int long long
#define ll long long
#define ll1 1ll
#define ONE 1ll
#define DBG 1
#define rep(i, a, b) for (int i = (a); i < (b); i++)
#define rrep(i, a, b) for (int i = (b)-1; i >= (a); i--)
#define loop(n) rep(loop, (0), (n))
#define all(c) begin(c), end(c)
const int INF =
sizeof(int) == sizeof(long long) ? 0x3f3f3f3f3f3f3f3fLL : 0x3f3f3f3f;
const int MOD = (int)(1e9) + 7;
const double PI = acos(-1);
const double EPS = 1e-9;
#define fi first
#define se second
#define pb push_back
#define eb emplace_back
using pii = pair<int, int>;
// template<class T> ostream &operator<<(ostream &os,T &t){dump(t);return os;}
template <typename T, typename S>
istream &operator>>(istream &is, pair<T, S> &p) {
	is >> p.first >> p.second;
	return is;
}
template <typename T, typename S>
ostream &operator<<(ostream &os, pair<T, S> &p) {
	os << p.first << " " << p.second;
	return os;
}

template <typename T> void printvv(const vector<vector<T>> &v) {
	cerr << endl;
	rep(i, 0, v.size()) rep(j, 0, v[i].size()) {
		if (typeid(v[i][j]).name() == typeid(INF).name() and v[i][j] == INF) {
			cerr << "INF";
		}
		else
			cerr << v[i][j];
		cerr << (j == v[i].size() - 1 ? '\n' : ' ');
	}
	cerr << endl;
}
/*
typedef __int128_t Int;
std::ostream &operator<<(std::ostream &dest, __int128_t value) {
std::ostream::sentry s(dest);
  if (s) {
	__uint128_t tmp = value < 0 ? -value : value;
	char buffer[128];
	char *d = std::end(buffer);
	do {
	  --d;
	  *d = "0123456789"[tmp % 10];
	  tmp /= 10;
	} while (tmp != 0);
	if (value < 0) {
	  --d;
	  *d = '-';
	}
	int len = std::end(buffer) - d;
	if (dest.rdbuf()->sputn(d, len) != len) {
	  dest.setstate(std::ios_base::badbit);
	}
  }
  return dest;
}

__int128 parse(string &s) {
  __int128 ret = 0;
  for (int i = 0; i < s.length(); i++)
	if ('0' <= s[i] && s[i] <= '9')
	  ret = 10 * ret + s[i] - '0';
  return ret;
}
*/

#ifndef _DEBUG
#define printvv(...)
#endif
void YES(bool f) { cout << (f ? "YES" : "NO") << endl; }
void Yes(bool f) { cout << (f ? "Yes" : "No") << endl; }
template <class T> bool chmax(T &a, const T &b) {
	if (a < b) {
		a = b;
		return true;
	}
	return false;
}
template <class T> bool chmin(T &a, const T &b) {
	if (a > b) {
		a = b;
		return true;
	}
	return false;
}
template <typename T> vector<T> compress(vector<T> &a, vector<T> &b) {
	// 座標圧縮
	vector<T> ret;
	ret.insert(ret.end(), all(a));
	ret.insert(ret.end(), all(b));
	sort(all(ret));
	ret.erase(unique(all(ret)), ret.end());
	rep(i, 0, a.size()) a[i] = distance(ret.begin(), lower_bound(all(ret), a[i]));
	rep(i, 0, b.size()) b[i] = distance(ret.begin(), lower_bound(all(ret), b[i]));
	return ret;
}

signed main(signed argc, char *argv[]) {
	cin.tie(0);
	ios::sync_with_stdio(false);
	cout << fixed << setprecision(12);

	pii s, t; cin >> s >> t;
	if (s.first >= t.first)swap(s, t);
	int N; cin >> N;
	vector<pii>v(N); rep(i, 0, N) { cin >> v[i]; }
	auto inrange = [&](int x, int y) { return min(s.first, t.first) <= x and x <= max(s.first, t.first) and min(s.second, t.second) <= y and y <= max(s.second, t.second); };
	vector<pii>w;
	rep(i, 0, v.size()) {
		if (not inrange(v[i].first, v[i].second))continue;
		if (s.second > t.second)v[i].second *= -1;
		w.emplace_back(v[i]);
	}
	sort(all(w));
	vector<int>dp(w.size() + 1, INF), xx(w.size() + 1);
	rep(i, 0, w.size()) {
		int d = lower_bound(all(dp), w[i].second) - dp.begin();
		dp[d] = w[i].second;
		xx[d] = w[i].first;
	}
	int cnt = lower_bound(all(dp), INF) - dp.begin();
	dump(dp);
	dump(cnt);
	int ss = (abs(s.first - t.first) + abs(s.second - t.second));
	int p = cnt;
	int q = 0;
	if (cnt == min(abs(s.first - t.first), abs(s.second - t.second)) + 1) {
		p--;
		q++;
	}
	double ans = 100 * ss - (20 - 5 * PI)*p + (10 * PI - 20)*q;

	cout << ans << endl;



	return 0;
}


Measured memory_bytes: 10476