import java.io.*; import java.util.*; import java.math.*; class Main166 { public static void out (Object out) { System.out.println(out); } public static void main (String[] args) throws IOException { BufferedReader br = new BufferedReader(new InputStreamReader(System.in)); String[] line = br.readLine().split(" "); int h = Integer.parseInt(line[0]); int w = Integer.parseInt(line[1]); long n = Long.parseLong(line[2]); long k = Long.parseLong(line[3]) % n; System.out.println((h * w) % n == k ? "YES" : "NO"); } }