#python solution
def kangaroo(x1, v1, x2, v2):
    #tests if intersection is not possible
    if (v1 == v2 and x1 != x2) or v2 > v1: 
        return "NO"
        
    k1 = x1
    k2 = x2
		
    #tests if intersection will happen at an integer
    while k1 < k2:
        k1 += v1
        k2 += v2
        if k1 > k2:
            return "NO"
            
    return "YES"