#include <iostream>
#include <vector>

using namespace std;

class q{
public:
    int head;
    int tail;
    int buffer_size = 8;
    int size;
    int* buffer;

    q();
    ~q();
    void push(int elem);
    int pop();
    void resize(int new_size);
};

q::q(){
    head = 0;
    tail = 0;
    size = 0;
    buffer = new int[buffer_size];
}

q::~q(){
    delete[] buffer;
}

void q::push(int elem){
    if (size >= buffer_size)
        resize(buffer_size*2);
    buffer[tail%buffer_size] = elem;
    size++;
    tail++;
}

int q::pop(){
    if (size>0)
      return buffer[head++%buffer_size];
    else
        return -1;
}

void q::resize(int new_size){
    int* tmp = new int[new_size];
    for (int i = 0; i < size; i++)
        tmp[i] = buffer[(head+i)%buffer_size];
    tail = size;
    head = 0;
    buffer_size = new_size;
    buffer = tmp;
}



int main() {
    q queue;
    int n;
    cin >> n;

    bool is_correct = true;
    for (int i = 0; i < n; i++){
        int a;
        cin >> a;
        if (a==2){
            int awaited_value;
            cin >> awaited_value;
            if (queue.pop() != awaited_value)
                is_correct = false;
        }
        else{
            int value;
            cin >> value;
            queue.push(value);
        }
    }

    if (is_correct)
        cout << "YES" << endl;
    else
        cout << "NO" << endl;
    return 0;
}