class Fill(object):
    def __init__(self):
        pass

    def constructor(self, data):
        data = list(map(int, data))
        self.H = data[0]
        self.W = data[1]
        self.N = data[2]
        self.K = data[3]

    def run(self):
        self.analysis()
    
    def analysis(self):
        
        if self.H*self.W % self.N == self.K % self.N:
            print("YES")
        else:
            print("NO")

if __name__=="__main__":
    data = input().split(" ")
    func = Fill()
    func.constructor(data)
    func.run()