L,R,M,K = map(int,input().split())
if K == 0:
    print('Yes')
elif L<= M <=R:
    print('Yes')
elif (L+R)%M ==0 and K%2 == 0:
    print('Yes')
elif (L+R)*(-L+R+1)/2%M==0 and K%(R-L+1)==0:
    print('Yes')
else:
    print('No')