Arkady has got an infinite plane painted in color 0. Then he draws n rectangles filled with paint with sides parallel to the Cartesian coordinate axes, one after another. The color of the i-th rectangle is i (rectangles are enumerated from 1 to n in the order he draws them). It is possible that new rectangles cover some of the previous ones completely or partially.

Count the number of different colors on the plane after Arkady draws all the rectangles.

Input

The first line contains a single integer n (1 ≤ n ≤ 100 000) — the number of rectangles.

The i-th of the next n lines contains 4 integers x_1, y_1, x_2 and y_2 (-10^9 ≤ x_1 < x_2 ≤ 10^9, -10^9 ≤ y_1 < y_2 ≤ 10^9) — the coordinates of corners of the i-th rectangle.

Output

In the single line print the number of different colors in the plane, including color 0.

Examples

Input

5
-1 -1 1 1
-4 0 0 4
0 0 4 4
-4 -4 0 0
0 -4 4 0


Output

5

Input

4
0 0 4 4
-4 -4 0 0
0 -4 4 0
-2 -4 2 4


Output

5

Note

<image> That's how the plane looks in the first sample

<image> That's how the plane looks in the second sample

0 = white, 1 = cyan, 2 = blue, 3 = purple, 4 = yellow, 5 = red. 
#include <bits/stdc++.h>
using namespace std;
namespace IO {
const int BUFFER_SIZE = 1 << 15;
char input_buffer[BUFFER_SIZE];
int input_pos = 0, input_len = 0;
void _update_input_buffer() {
  input_len = fread(input_buffer, sizeof(char), BUFFER_SIZE, stdin);
  input_pos = 0;
  if (input_len == 0) input_buffer[0] = EOF;
}
inline char next_char(bool advance = true) {
  if (input_pos >= input_len) _update_input_buffer();
  return input_buffer[advance ? input_pos++ : input_pos];
}
template <typename T>
inline void read_int(T &number) {
  bool negative = false;
  number = 0;
  while (!isdigit(next_char(false)))
    if (next_char() == '-') negative = true;
  do {
    number = 10 * number + (next_char() - '0');
  } while (isdigit(next_char(false)));
  if (negative) number = -number;
}
template <typename T, typename... Args>
inline void read_int(T &number, Args &...args) {
  read_int(number);
  read_int(args...);
}
}  // namespace IO
struct rect {
  int x1, x2, y1, y2;
};
struct event {
  int id, x, y1, y2;
  bool operator<(const event &other) const { return x < other.x; }
};
int N;
vector<rect> rects;
vector<bool> visible;
vector<bool> erased;
struct tree_node {
  priority_queue<int> colors;
  int max_not_done = -1;
  int minimum = -1;
};
int tree_n;
vector<tree_node> tree;
void tree_init(int n) {
  tree_n = 1;
  while (tree_n < n) tree_n *= 2;
  tree.assign(2 * tree_n, {});
}
void tree_join(int position) {
  if (position < tree_n) {
    tree[position].minimum =
        min(tree[2 * position].minimum, tree[2 * position + 1].minimum);
    tree[position].max_not_done = max(tree[2 * position].max_not_done,
                                      tree[2 * position + 1].max_not_done);
  } else {
    tree[position].minimum = tree[position].max_not_done = -1;
  }
  while (!tree[position].colors.empty() && erased[tree[position].colors.top()])
    tree[position].colors.pop();
  if (!tree[position].colors.empty()) {
    int biggest = tree[position].colors.top();
    tree[position].minimum = max(tree[position].minimum, biggest);
    if (biggest > tree[position].max_not_done)
      tree[position].max_not_done =
          visible[biggest] || biggest < tree[position].minimum ? -1 : biggest;
  }
}
void tree_update(int position, int start, int end, int a, int b, int id) {
  if (a <= start && end <= b) {
    if (id >= 0 && id < N) tree[position].colors.push(id);
    tree_join(position);
    return;
  }
  if (position >= tree_n) return;
  int mid = (start + end) / 2;
  if (a < mid) tree_update(2 * position, start, mid, a, b, id);
  if (b > mid) tree_update(2 * position + 1, mid, end, a, b, id);
  tree_join(position);
}
int main() {
  IO::read_int(N);
  rects.resize(N);
  vector<int> Y;
  for (rect &r : rects) {
    IO::read_int(r.x1, r.y1, r.x2, r.y2);
    Y.push_back(r.y1);
    Y.push_back(r.y2);
  }
  sort(Y.begin(), Y.end());
  Y.resize(unique(Y.begin(), Y.end()) - Y.begin());
  for (rect &r : rects) {
    r.y1 = lower_bound(Y.begin(), Y.end(), r.y1) - Y.begin();
    r.y2 = lower_bound(Y.begin(), Y.end(), r.y2) - Y.begin();
  }
  vector<event> events;
  for (int i = 0; i < N; i++) {
    events.push_back({i, rects[i].x1, rects[i].y1, rects[i].y2});
    events.push_back({N + i, rects[i].x2, rects[i].y1, rects[i].y2});
  }
  sort(events.begin(), events.end());
  visible.assign(N, false);
  erased.assign(N, false);
  tree_init(Y.size());
  for (int i = 0, j = 0; i < (int)events.size(); i = j) {
    while (j < (int)events.size() && events[i].x == events[j].x) {
      if (events[j].id >= N) erased[events[j].id - N] = true;
      tree_update(1, 0, tree_n, events[j].y1, events[j].y2, events[j].id);
      j++;
    }
    while (tree[1].max_not_done >= 0) {
      int id = tree[1].max_not_done;
      visible[id] = true;
      tree_update(1, 0, tree_n, rects[id].y1, rects[id].y2, -1);
    }
  }
  int visible_count = 1;
  for (int i = 0; i < N; i++) visible_count += visible[i];
  cout << visible_count << '\n';
}
