#include <bits/stdc++.h>
 
using namespace std;
using ll = long long;
// #define int ll
using PII = pair<int, int>;
 
#define FOR(i, a, n) for (ll i = (ll)a; i < (ll)n; ++i)
#define REP(i, n) FOR(i, 0, n)
#define ALL(x) x.begin(), x.end()
 
template<typename T> T &chmin(T &a, const T &b) { return a = min(a, b); }
template<typename T> T &chmax(T &a, const T &b) { return a = max(a, b); }
template<typename T> bool IN(T a, T b, T x) { return a<=x&&x<b; }
template<typename T> T ceil(T a, T b) { return a/b + !!(a%b); }

template<typename T> vector<T> make_v(size_t a) { return vector<T>(a); }
template<typename T,typename... Ts>
auto make_v(size_t a,Ts... ts) { 
  return vector<decltype(make_v<T>(ts...))>(a,make_v<T>(ts...));
}
template<typename T,typename V> typename enable_if<is_class<T>::value==0>::type
fill_v(T &t, const V &v) { t=v; }
template<typename T,typename V> typename enable_if<is_class<T>::value!=0>::type
fill_v(T &t, const V &v ) { for(auto &e:t) fill_v(e,v); }

template<class S,class T>
ostream &operator <<(ostream& out,const pair<S,T>& a){
  out<<'('<<a.first<<','<<a.second<<')'; return out;
}
template<typename T>
istream& operator >> (istream& is, vector<T>& vec){
  for(T& x: vec) {is >> x;} return is;
}
template<class T>
ostream &operator <<(ostream& out,const vector<T>& a){
  out<<'['; for(T i: a) {out<<i<<',';} out<<']'; return out;
}

int dx[] = {0, 1, 0, -1}, dy[] = {1, 0, -1, 0}; // DRUL
const int INF = 1<<30;
const ll LLINF = 1LL<<60;
const int MOD = 1000000007;

/**
* @brief binary index tree
* @details 抽象化したBIT
*/
template <typename T>
class BIT {
private:
  // データ
  vector<T> bit;
  // 単位元, 要素数
  int neutral = 0;
  // 更新クエリ, 区間クエリ
  function<T(T,T)> f = [](const T l, const T r) -> T { return l+r; },
                   g = [](const T l, const T r) -> T { return l+r; };
public:
  // 初期化
  BIT(int n_ = 1e5) { init(n_); }
  void init(int n_ = 1e5) { bit.assign(n_+1, neutral); }
  // iに対する点更新クエリ
  void update(int i, T w) {
    for(int x = i+1; x < (int)bit.size(); x += x&-x) bit[x] = f(bit[x], w);
  }
  // [0,i]に対する区間クエリ
  T query(int i) {
    T ret = neutral;
    for(int x = i+1; x > 0; x -= x & -x) ret = g(ret, bit[x]);
    return ret;
  }
};

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

  int x1, y1, x2, y2;
  cin >> x1 >> y1 >> x2 >> y2;
  int n;
  cin >> n;
  vector<int> x(n), y(n);
  REP(i, n) cin >> x[i] >> y[i];

  if(x2 < x1) {
    swap(x1, x2);
    swap(y1, y2);
  }
  if(y2 < y1) {
    y1 *= -1, y2 *= -1;
    REP(i, n) y[i] *= -1;
  }

  vector<PII> vp;
  REP(i, n) {
    if(x1 <= x[i] && x[i] <= x2 && y1 <= y[i] && y[i] <= y2) {
      vp.push_back({x[i], y[i]});
    }
  }
  sort(ALL(vp));
  vector<int> ny;
  REP(i, vp.size()) ny.push_back(vp[i].second);

  // nyのLISを求める
  vector<int> dp(ny.size(), INF);
  REP(i, ny.size()) {
    *lower_bound(ALL(dp), ny[i]) = ny[i];
  }
  int lis = lower_bound(ALL(dp), INF) - dp.begin();

  // cout << ma << endl;
  long double PI = acos(-1);
  long double ans = 100 * (ll)(x2-x1) + 100 * (ll)(y2-y1);
  ans += lis * (5*PI-20);
  if(lis == min(x2-x1,y2-y1)+1) ans += 5*PI;

  cout << fixed << setprecision(15) << ans << endl;

  return 0;
}


Measured memory_bytes: 5232