l,r,m,k = map(int,input().split())

l %= m
r %= m

if l == 0 or k == 0 or l > r or k % m == 0:
    print('Yes')
else:
    min_num = l*k
    max_num = r*k
    if min_num // m != max_num // m:
        print('Yes')
    elif min_num % m == 0:
        print('Yes')
    else:
        print('No')