x,y = map(int,input().split())
x,y = x*10/36,y*10/36
n = int(input())
A = [int(i)for i in input().split()] 
for i in range(n-1):
    a = A[i] // x
    b = a * y
    if b > A[i+1]:
        print("NO")
        break
else:
    print("YES")