QueueOnArray

#include <assert.h>
#include <iostream>

class Queue {
 public:
  explicit Queue(int size);
  ~Queue();
  void push_back(int value);
  int pop_front();
  bool IsEmpty() const;
 private:
  int* buffer_;
  int buffer_size_;
  int head_;
  int tail_;
};
Queue::Queue(int size) : buffer_size_(size), head_(0), tail_(0) {
  buffer_ = new int[buffer_size_];
}
Queue::~Queue() {
  delete [] buffer_;
}
void Queue::push_back(int value) {
  assert((tail_ + 1) % buffer_size_ != head_);
  buffer_[tail_] = value;
  tail_ = (tail_ + 1) % buffer_size_;
}
int Queue::pop_front() {
  assert(head_ != tail_);
  int temp_data = buffer_[head_];
  head_ = (head_ + 1) % buffer_size_;
  return temp_data;
}
bool Queue::IsEmpty() const {
  return (tail_ == head_);
}
int main() {
  int num = 0;
  std::cin >> num;
  Queue queue(num);
  for (int i = 0; i < num; i++) {
    int operation = 0;
    int value = 0;
    std::cin >> operation >> value;
    switch (operation) {
      case 3:
        queue.push_back(value);
        break;
      case 2:
      {
        if ((queue.IsEmpty() && value != -1) ||
            (!queue.IsEmpty() && queue.pop_front() != value)) {
          std::cout << "NO" << std::endl;
          return 0;
        }
        break;
      }
      default:
        break;
    }
  }
  std::cout << "YES" << std::endl;
}