# -*- coding: utf-8 -*-
"""
No.166 マス埋めゲーム
https://yukicoder.me/problems/no/166

"""
import sys
from sys import stdin
input = stdin.readline


def main(args):
    H, W, N, K = map(int, input().split())
    if N == K:
        K = 0
    if H * W % N == K:
        print('YES')
    else:
        print('NO')



if __name__ == '__main__':
    main(sys.argv[1:])