# -*- coding: utf-8 -*-

import sys

def input(): return sys.stdin.readline().strip()
def list2d(a, b, c): return [[c] * b for i in range(a)]
def list3d(a, b, c, d): return [[[d] * c for j in range(b)] for i in range(a)]
def list4d(a, b, c, d, e): return [[[[e] * d for j in range(c)] for j in range(b)] for i in range(a)]
def ceil(x, y=1): return int(-(-x // y))
def INT(): return int(input())
def MAP(): return map(int, input().split())
def LIST(N=None): return list(MAP()) if N is None else [INT() for i in range(N)]
def Yes(): print('Yes')
def No(): print('No')
def YES(): print('YES')
def NO(): print('NO')
sys.setrecursionlimit(10 ** 9)
INF = 10 ** 18
MOD = 10 ** 9 + 7
EPS = 10 ** -10

x, y = MAP()
N = INT()
A = LIST()

B = [A[0]]
for i in range(N-1):
    B.append(A[i+1] - A[i])

x = x * 1000 / 3600
y = y * 1000 / 3600

curx = cury = 0
for i in range(N-1):
    time = B[i] / x
    curx += B[i]
    cury += time * y
    if cury-EPS > A[i+1]:
        NO()
        exit()
YES()