X,Y = [int(i) for i in input().split()]
N = int(input())
A = [int(i) for i in input().split()]
lost = 0
for i in range(1,N):
    if X/3600/A[i-1] < Y/3600/A[i]:
        lost = 1
if lost == 1:
    print("NO")
else:
    print("YES")