#include <bits/stdc++.h>
using namespace std;

typedef long long   signed int LL;
typedef long long unsigned int LU;

#define incID(i, l, r) for(int i = (l)    ; i <  (r); i++)
#define incII(i, l, r) for(int i = (l)    ; i <= (r); i++)
#define decID(i, l, r) for(int i = (r) - 1; i >= (l); i--)
#define decII(i, l, r) for(int i = (r)    ; i >= (l); i--)
#define  inc(i, n) incID(i, 0, n)
#define inc1(i, n) incII(i, 1, n)
#define  dec(i, n) decID(i, 0, n)
#define dec1(i, n) decII(i, 1, n)

#define inII(v, l, r) ((l) <= (v) && (v) <= (r))
#define inID(v, l, r) ((l) <= (v) && (v) <  (r))

#define PB push_back
#define EB emplace_back
#define MP make_pair
#define FI first
#define SE second
#define PQ priority_queue

#define  ALL(v)  v.begin(),  v.end()
#define RALL(v) v.rbegin(), v.rend()
#define  FOR(it, v) for(auto it =  v.begin(); it !=  v.end(); ++it)
#define RFOR(it, v) for(auto it = v.rbegin(); it != v.rend(); ++it)

template<typename T> bool   setmin(T & a, T b) { if(b <  a) { a = b; return true; } else { return false; } }
template<typename T> bool   setmax(T & a, T b) { if(b >  a) { a = b; return true; } else { return false; } }
template<typename T> bool setmineq(T & a, T b) { if(b <= a) { a = b; return true; } else { return false; } }
template<typename T> bool setmaxeq(T & a, T b) { if(b >= a) { a = b; return true; } else { return false; } }
template<typename T> T gcd(T a, T b) { return (b == 0 ? a : gcd(b, a % b)); }
template<typename T> T lcm(T a, T b) { return a / gcd(a, b) * b; }

// ---- ----

template<typename T> class SegTree {
private:
	T * a = NULL;
	int M, S;
	T (*F)(T, T);
	T I;

public:
	// [0, size) が使用可能になる、func が演算、id は単位元
	void init(int size, T (*func)(T, T), T id) {
		assert(size > 0);
		M = size;
		F = func;
		I = id;
		S = 1;
		while(S < size) { S *= 2; }
		delete[] a;
		a = new T[S * 2];
		inc(i, S * 2) { a[i] = I; }
	}
	
	// 参照（値を変更した後は calc() を呼ぶこと）
	T & operator[](int p) {
		assert(inID(p, 0, M));
		p += S;
		return a[p];
	}
	
	// テーブルの再計算
	void calc() {
		decID(i, 1, S) {
			a[i] = F(a[i * 2], a[i * 2 + 1]);
		}
	}
	
	// a[p] を v に変更し再計算
	void update(int p, T v) {
		assert(inID(p, 0, M));
		p += S;
		a[p] = v;
		while(p != 1) {
			p /= 2;
			a[p] = F(a[p * 2], a[p * 2 + 1]);
		}
	}
	
	// [l, r) に f を適用した結果を返す
	T range(int l, int r) {
		assert(inII(l, 0, M));
		assert(inII(r, 0, M));
		// if(l > r) { return F(range(l, M), range(0, r)); }
		assert(l <= r);
		l += S;
		r += S;
		
		T v = I, w = I;
		while(l < r) {
			if(l + 1 == r) { v = F(v, a[l]); break; }
			
			if(l % 2 == 1) { v = F(v, a[l]); }
			if(r % 2 == 1) { w = F(a[r - 1], w); }
			
			l = (l + 1) / 2;
			r = r / 2;
		}
		
		return F(v, w);
	}
};

template<typename T> T MAX(T x, T y) { return max(x, y); }

// ---- ---- ---- ----

/*
// 使用例
int main() {
	int n = 10;
	SegTree<int> st;
	st.init(n, prod, 1);
	
	inc(i, n) { st[i] = (i * i * i + 2) % 5; }
	st.calc();
	
	inc(i, n) { printf("%2d", i); } cout << endl;
	inc(i, n) { printf("%2d", st[i]); } cout << endl;
	
	cout << st.range(3, 7) << endl;
	
	return 0;
}
*/

int n, sx, sy, gx, gy, x[200000], y[200000];
double PI = 3.1415926535897932;
pair<int, int> p[200000];
map<int, int> m;

int main() {
	cin >> sx >> sy >> gx >> gy >> n;
	inc(i, n) { cin >> x[i] >> y[i]; }
	
	double ans = -123.4;
	if(sx == gx) {
		if(sy > gy) { swap(sy, gy); }
		LL c = 0;
		inc(i, n) { if(x[i] == sx && inII(y[i], sy, gy)) { c++; } }
		ans = 100.0 * (gy - sy) + c * (10.0 * PI - 20.0);
	} else if(sy == gy) {
		if(sx > gx) { swap(sx, gx); }
		LL c = 0;
		inc(i, n) { if(y[i] == sy && inII(x[i], sx, gx)) { c++; } }
		ans = 100.0 * (gx - sx) + c * (10.0 * PI - 20.0);
	} else {
		LL M = 1e8 - 1;
		if(sx > gx) {
			sx = M - sx;
			gx = M - gx;
			inc(i, n) { x[i] = M - x[i]; }
		}
		if(sy > gy) {
			sy = M - sy;
			gy = M - gy;
			inc(i, n) { y[i] = M - y[i]; }
		}
		
		inc(i, n) { p[i] = MP(y[i], x[i]); }
		sort(p, p + n);
		inc(i, n) { m[p[i].FI] = i; }
		
		inc(i, n) { p[i] = MP(x[i], y[i]); }
		sort(p, p + n);
		
		SegTree<int> st;
		st.init(n, MAX, 0);
		inc(i, n) {
			if(inII(p[i].FI, sx, gx) && inII(p[i].SE, sy, gy)) {
				st.update(m[p[i].SE], st.range(0, m[p[i].SE]) + 1);
			}
		}
		int c = st.range(0, n);
		// cout << c << endl;
		int xx = gx - sx;
		int yy = gy - sy;
		ans = 100.0 * (xx + yy) + c * (5.0 * PI - 20.0) + (c == min(xx, yy) + 1 ? 5.0 * PI : 0.0);
	}
	
	printf("%.13f\n", ans);
	
	return 0;
}


Measured memory_bytes: 14848