#include <iostream>
#include <vector>
#include <algorithm>
#include <map>
#define f first
#define s second
using namespace std;

pair <char, int>a[100002];
void solve() {
	int n;
	cin >> n;
	cin >> a[0].f >> a[0].s;
	for (int i = 1; i < n; i++) {
		cin >> a[i].f >> a[i].s;
	}
	if (a[0].f == '*' || a[n - 1].f == '*') {
		cout << "NO";
		return;
	}
	for (int i = 1; i < n-1; i++) {
		if (a[i].f == '#') {
			bool check = true;
			for (int j = i+1; j < n; j++) {
				if (a[j].s - a[i].s > 2) {
					cout << "NO";
					return;
				}
				if (a[j].f == '#') {
					check = false;
					i = j - 1;
					break;
				}
			}
			if (check) {
				cout << "NO";
				return;
			}
		}
	}
	cout << "YES";
}

int main() {
	int t = 1;
	//cin >> t;
	while(t--){
		solve();
	}
}