x, y = [int(i)/36 for i in input().strip().split(" ")]
N = int(input())
A = [int(i) for i in input().strip().split(" ")]

lost = False
for i in range(N-1, 0, -1):
    Y_time = A[i] / y
    X_dist = x * Y_time
    if X_dist < A[i-1]:
        lost = True
        break

if lost:
    print("NO")
else:
    print("YES")