#include <bits/stdc++.h>
#include <random>

using namespace std;

typedef unsigned long long ull;
typedef long long ll;
typedef double ld;
//#define ll __int128
#define int ll
//#define int ll
//#define char ll
typedef vector<char> vc;
typedef vector<vc> vvc;
typedef vector<vvc> vvvc;
typedef pair<int, int> pii;
typedef pair<pii, pii> piii;
typedef pair<ll, ll> pll;
typedef vector<int> vi;
typedef vector<pii> vpi;
typedef vector< vi > vvi;
typedef vector< vvi > vvvi;
typedef vector<short> vs;
typedef vector<vs> vvs;
typedef vector<vvs> vvvs;
typedef vector<ll> vl;
typedef vector<vl> vvl;
typedef vector<vvl> vvvl;
typedef vector<ld> vld;
typedef vector<vld> vvld;
typedef vector<vvld> vvvld;
typedef vector<string> vst;
typedef vector<vst> vvst;
typedef pair<ld, ld> pld;

#define inmin(a, b) a = min(a, (b))
#define inmax(a, b) a = max(a, (b))
#define ALL(a) a.begin(),a.end()
#define RALL(a) a.rbegin(),a.rend()
#define sqr(x) ((x) * (x))
#define fori(i, n) for(int i = 0; i < int(n); ++i)
#define SZ(a) ((int)((a).size()))
#define triple(T) tuple<T, T, T>
#define quad(T) tuple<T, T, T, T>
#define watch(x) cerr << (#x) << " = " << (x) << endl;

#ifdef MAX_HOME
#define cerr cout
#else
#define cerr if (false) cerr
#endif

const ld PI = (ld)2.0 * acosl(0.0);
#define rand shittttty_shit
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
mt19937_64 rng_64(chrono::steady_clock::now().time_since_epoch().count());

const string DIGITS = "0123456789";
const string ALPH = "abcdefghijklmnopqrstuvwxyz";


template <class T0, class T1>
inline ostream & operator << (ostream &out, pair<T0, T1> &a) {
    return out << "{" << a.first << ", " << a.second << "}";
}

template <class T0, class T1>
inline istream & operator >> (istream &in, pair<T0, T1> &a) {
    return in >> a.first >> a.second;
}

template <class T0, class T1, class T2>
inline ostream & operator << (ostream &out, tuple<T0, T1, T2> &a) {
    return out << "{" << get<0>(a) << ", " << get<1>(a) << ", " << get<2>(a) << "}";
}

template <class T0, class T1, class T2, class T3>
inline ostream & operator << (ostream &out, tuple<T0, T1, T2, T3> &a) {
    return out << "{" << get<0>(a) << ", " << get<1>(a) << ", " << get<2>(a) << ", " <<  get<3>(a) << "}";
}

template<class T>
inline ostream & operator << (ostream &out, vector<T> &a) {
    out << "[";
    fori (i, a.size())
        out << a[i] << vector<string>{", ", "]  "}[i + 1 == a.size()];
    return out;
}


void smain();



signed main() {
    ios::sync_with_stdio(0);
    cin.tie(0); cout.tie(0);

#ifdef MAX_HOME
    freopen("input.txt", "r", stdin);
    clock_t start = clock();
#endif
    cout << setprecision(15) << fixed;
    smain();
#ifdef MAX_HOME
    cout << "\n\n\n\nTOTAL EXECUTION TIME: " << float( clock () - start ) /  CLOCKS_PER_SEC << endl;
#endif
    return 0;
}

int sx, sy, tx, ty;
vector<pii> points;
int H, W;
#ifdef MAX_HOME
const int N = 5;
#else
const int N = 1e8;
#endif

void smain() {
    int n;
    cin >> sx >> sy >> tx >> ty >> n;
    points.resize(n);
    fori (i, n) {
        cin >> points[i].first >> points[i].second;
    }

    if (sx > tx) {
        sx = N - sx;
        tx = N - tx;
        for (auto & point : points) {
            point.first = N - point.first;
        }
    }
    if (sy > ty) {
        sy = N - sy;
        ty = N - ty;
        for (auto & point : points) {
            point.second = N - point.second;
        }
    }
    vector<pii> npoints;
    H = tx - sx, W = ty - sy;
    for (auto point : points) {
        point.first -= sx;
        point.second -= sy;
        if (point.first >= 0 && point.first <= H && point.second >= 0 && point.second <= W) {
            npoints.push_back(point);
        }
    }
    points = npoints;

    sort(ALL(points));

    set<pii> dp;
    dp.insert({-1, 0});
    int cnt = 0;
    for (auto point : points) {
        auto it = dp.lower_bound({point.second, -1});
        it--;
        int mx = it->second + 1;
        inmax(cnt, mx);
        dp.insert({point.second, mx});
        while (true) {
            it = dp.upper_bound({point.second, mx});
            if (it == dp.end())
                break;
            if (it->second > mx)
                break;
            dp.erase(it);
        }
    }

    ld ans = (ld)100.0 * (H + W) + (ld)cnt * ((ld)5.0 * PI - 20.0);

    if (cnt == min(H, W) + 1) {
        ans += (ld)5.0 * PI;
    }

    cout << ans;
}

Measured memory_bytes: 19948