x, y = map(int, input().split())
n = int(input())
p = list(map(int, input().split()))

def f(x, y, n, p):
  x_s = x / 60 / 60
  y_s = y / 60 / 60
  for i in range(n - 1):
    if y_s * (p[i] / x_s) > p[i+1]:
      return 'NO'
  
  return ('YES')

print(f(x, y, n, p))