import java.util.*; import java.io.*; import java.math.*; public class No512 { public static void main(String[] args) { Scanner sc = new Scanner(System.in); double x = sc.nextDouble() * 1000 / 3600, y = sc.nextDouble() * 1000 / 3600; int n = sc.nextInt(); int[] a = new int[n]; for(int i = 0; i < n; i++) { a[i] = sc.nextInt(); } for(int i = 0; i < n - 1; i++) { double j = a[i] / x; // System.out.println("i = " + (i + 1) + " a[i + 1] = " + a[i + 1] + ": j * y = " + (int)(j * y)); // y * a[i] * x > a[i + 1] → y * a[i] > a[i + 1] * x if((int)(y * a[i]) > a[i + 1] * x) { System.out.println("NO"); return; } } System.out.println("YES"); } }