using System; using System.Collections; using System.Collections.Generic; using System.Collections.Specialized; using System.Text; using System.Text.RegularExpressions; using System.IO; using System.Linq; class Program { static void Main() { new Magatro().Solve(); } } class Magatro { private int X, Y; private int N; private decimal[] A; private void Scan() { var line = Console.ReadLine().Split(' '); X = int.Parse(line[0]); Y = int.Parse(line[1]); N = int.Parse(Console.ReadLine()); A = Console.ReadLine().Split(' ').Select(i => int.Parse(i) * 3.6m).ToArray(); } public void Solve() { Scan(); decimal sumX = 0; decimal sumY = A[0]; for (int i = 0; i < N - 1; i++) { sumX += A[i]; sumY += A[i + 1]; if (sumX * Y / X > sumY) { Console.WriteLine("NO"); return; } } Console.WriteLine("YES"); } }