from collections import defaultdict
from bisect import bisect

def main():
    X, Y = map(int, input().split())
    N = int(input())
    A_list = list(map(int, input().split()))

    for i in range(N):
        a = A_list[i]
        t = a / X
        s = Y * t
        p = bisect(A_list, s)
        if p > i + 1 and A_list[i + 1] != s:
            print("NO")
            break
    else:
        print("YES")


if __name__ == '__main__':
    main()