# coding: utf-8 import array, bisect, collections, copy, heapq, itertools, math, random, re, string, sys, time sys.setrecursionlimit(10 ** 7) INF = 10 ** 20 MOD = 10 ** 9 + 7 def II(): return int(input()) def ILI(): return list(map(int, input().split())) def IAI(LINE): return [ILI() for __ in range(LINE)] def IDI(): return {key: value for key, value in ILI()} def solve(X, Y, N, A): x_m = X * 1000 / 3600 y_m = Y * 1000 / 3600 l_x = [a / x_m for a in A] l_y = [a / y_m for a in A] ans = "NO" for i in range(N - 1): if l_y[i + 1] < l_x[i]: break else: ans = "YES" return ans def main(): X, Y = ILI() N = II() A = ILI() print(solve(X, Y, N, A)) if __name__ == "__main__": main()