def gcd(a,b):
    while b != 0:
        a, b = b, a % b
    return a

l, r, m, k = map(int,input().split())
if k == 0:
    print("Yes")
else:
    if r - l + 1 >= m:
        print("Yes")
    else:
        lm = l % m
        rm = r % m
        mk = m % k
        if lm > rm:
            print("Yes")
        else:
            mkgcd = gcd(m,k)
            if lm <= m//mkgcd <= rm:
                print("Yes")
            elif rm-lm+1 <= mkgcd:
                print("Yes")
            else:
                print("No")