X_km_h, Y_km_h = list(map(int, input().split())) N = int(input()) A_m = list(map(int, input().split())) X_m_s = X_km_h * 1000 / 60 / 60 Y_m_s = Y_km_h * 1000 / 60 / 60 ans = "YES" for i in range(N - 1): X_s = A_m[i] / X_m_s Y_m = Y_m_s * X_s if Y_m > A_m[i + 1]: ans = "NO" break print(ans)