/*
СТРОИМ СТЕНУ РАБОТЯГИ!
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*/
#include <iostream>
#include <vector>
#include <string>
#include <algorithm>
#include <cstdio>
#include <numeric>
#include <cstring>
#include <ctime>
#include <cstdlib>
#include <set>
#include <map>
#include <unordered_map>
#include <unordered_set>
#include <list>
#include <cmath>
#include <bitset>
#include <cassert>
#include <queue>
#include <stack>
#include <deque>
    
     
     
using namespace std;
template<typename T1, typename T2>inline void chkmin(T1 &x, T2 y) { if (x > y) x = y; }
template<typename T1, typename T2>inline void chkmax(T1 &x, T2 y) { if (x < y) x = y; }
/** Interface */
     
inline int readChar();
template <class T = int> inline T readInt(); 
template <class T> inline void writeInt( T x, char end = 0 );
inline void writeChar( int x ); 
inline void writeWord( const char *s );
     
/** Read */
     
static const int buf_size = 4096;
     
inline int getChar() {
    static char buf[buf_size];
    static int len = 0, pos = 0;
    if (pos == len) {
        pos = 0, len = fread(buf, 1, buf_size, stdin);
    }
    if (pos == len) {
        return -1;
    }
    return buf[pos++];
}
     
inline int readChar() {
    int c = getChar();
    while (c <= 32) {
        c = getChar();
    }
    return c;
}
     
template <class T>
inline T readInt() {
    int s = 1, c = readChar();
    T x = 0;
    if (c == '-')
        s = -1, c = getChar();
    while ('0' <= c && c <= '9')
        x = x * 10 + c - '0', c = getChar();
    return s == 1 ? x : -x;
}
     
/** Write */
     
static int write_pos = 0;
static char write_buf[buf_size];
     
inline void writeChar( int x ) {
    if (write_pos == buf_size)
        fwrite(write_buf, 1, buf_size, stdout), write_pos = 0;
    write_buf[write_pos++] = x;
}
     
template <class T> 
inline void writeInt( T x, char end ) {
    if (x < 0)
        writeChar('-'), x = -x;
     
    char s[24];
    int n = 0;
    while (x || !n)
        s[n++] = '0' + x % 10, x /= 10;
    while (n--)
        writeChar(s[n]);
    if (end)
        writeChar(end);
}
     
inline void writeWord( const char *s ) {     while (*s)
writeChar(*s++); }
     
struct Flusher {
    ~Flusher() {
        if (write_pos)
            fwrite(write_buf, 1, write_pos, stdout), write_pos = 0;
    }
} flusher;
   
   
#define sz(c) (int)(c).size()
#define all(c) (c).begin(), (c).end()
#define rall(c) (c).rbegin(), (c).rend()
#define left left228
#define right right228
#define next next228
#define rank rank228
#define prev prev228
#define y1 y1228
#define y2 y2228
const int MAXN = 200001;
const long double Pi = 3.1415926535897932384626433832;


int x1, y1, x2, y2;
int n;
int x[MAXN], y[MAXN];
int d[MAXN * 3];


void change(int i, int xs) {
    d[i] = xs;
    while (i >> 1 > 0) {
        i >>= 1;
        d[i] = max(d[i << 1], d[(i << 1) + 1]);
    }
}


int rmq(int v, int vl, int vr, int l, int r) {
    if (vl > r || vr < l) {
        return 0;
    }
    if (l <= vl && vr <= r) {
        return d[v];
    }
    return max(rmq(v << 1, vl, (vl + vr) >> 1, l, r), rmq((v << 1) + 1, ((vl + vr) >> 1) + 1, vr, l, r));
}


int where[MAXN];


int main() {
    x1 = readInt(), y1 = readInt(), x2 = readInt(), y2 = readInt();
    if (x1 > x2) {
        swap(x1, x2);
        swap(y1, y2);
    }
    if (x1 == x2) {
        if (y1 > y2) {
            swap(y1, y2);
        }
    }
    long double ans = 100.0 * abs(x1 - x2) + 100.0 * abs(y1 - y2);
    n = readInt();
    vector<pair<int, int> > st;
    int cnts = 0;
    for (int i = 0; i < n; i++) {
        x[i] = readInt(), y[i] = readInt();
        if (x[i] >= x1 && x[i] <= x2) {
            if (y[i] >= min(y1, y2) && y[i] <= max(y1, y2)) {
                st.push_back(make_pair(x[i], y[i]));
                if (x1 == x2 || y1 == y2) {
                    cnts++;
                }
            }
        }
    }
    if (x1 == x2 || y1 == y2) {
        printf("%.16lf\n", (double)(ans + cnts * (Pi * 10 - 20.0)));
        return 0;
    }
    sort(all(st));
    n = sz(st);
    vector<pair<int, int> > g;
    for (int i = 0; i < n; i++) {
        g.push_back(make_pair(st[i].second, i));
    }
    sort(all(g));
    for (int i = 0; i < n; i++) {
        where[g[i].second] = i;
    }
    int ss = 1;
    while (ss < n) {
        ss <<= 1;
    }
    long double res = 1e18;
    int cnt = 0;
    for (int i = 0; i < n; i++) {
        int cur = 1 + (y1 > y2 ? rmq(1, 1, ss, where[i] + 1, ss): rmq(1, 1, ss, 1, where[i] + 1));
        chkmax(cnt, cur);
        change(ss + where[i], cur);
    }
    double add = 0.0;
    if (cnt == min(abs(x1 - x2), abs(y1 - y2)) + 1) {
        add = Pi * 10.0 - 20.0 + (20.0 - Pi * 5.0);
    }
    chkmin(res, ans - (20.0 - Pi * 5.0) * cnt + add);
    printf("%.16lf\n", (double)res); 
    return 0;   
}


Measured memory_bytes: 8048