using System;
using System.Linq;

public class yukicoder
{
	
	public static double kirotometer(double n)
	{
		return (n * 1000) / 3600;
	}

    public static void Main()
    {
		double[] speed = Console.ReadLine().Split(' ').Select(x => double.Parse(x)).ToArray();
		double a = kirotometer(speed[0]);
		double b = kirotometer(speed[1]);
		double len = double.Parse(Console.ReadLine());
		double[] cross = Console.ReadLine().Split(' ').Select(x => double.Parse(x)).ToArray();
		double wktime = 0;
		double ynow = 0;
		string answer = "YES";
		
		for(int i = 0; i < cross.Length - 2; i++)
		{
			wktime = cross[i] / a;
			ynow = b * wktime;
			if(ynow > cross[i + 1])
			{
				answer = "NO";
				break;
			}
		}
		
		Console.WriteLine(answer);
    }
}