#include "bits/stdc++.h"
using namespace std;
typedef long long ll;
const ll MOD = 1e9 + 7;
const double PI = 3.141592653589793238;
const double EPS = 1e-10;
typedef pair<ll, ll> P;
int main() {
	ll x1, y1, x2, y2;
	cin >> x1 >> y1 >> x2 >> y2;
	if (x1 > x2) {
		swap(x1, x2);
		swap(y1, y2);
	}
	int N;
	cin >> N;
	vector<P> pos;
	for (int i = 0; i < N; i++) {
		ll X, Y;
		cin >> X >> Y;
		if (x1 > X || X > x2) continue;
		if (y1 <= y2) {
			if (y1 > Y || Y > y2) continue;
			pos.emplace_back(X, Y);
		}
		else {
			if (y2 > Y || Y > y1) continue;
			pos.emplace_back(X, -Y);
		}
	}
	sort(pos.begin(), pos.end());
	int n = pos.size();
	vector<int> dp(n);
	fill(dp.begin(), dp.end(), 1 << 30);
	for (int i = 0; i < n; i++) {
		*lower_bound(dp.begin(), dp.end(), pos[i].second) = pos[i].second;
	}
	int cnt = lower_bound(dp.begin(), dp.end(), 1 << 30) - dp.begin();
	double ans = (abs(x2 - x1) + abs(y2 - y1)) * 100;
	if (cnt == min(abs(x1 - x2), abs(y1 - y2)) + 1) {
		ans += (5 * PI - 20)*(cnt - 1) + (10 * PI - 20);
	}
	else {
		ans += (5 * PI - 20)*cnt;
	}
	printf("%.15lf\n", ans);
}