import java.io.*;
import java.math.*;
import java.security.*;
import java.text.*;
import java.util.*;
import java.util.concurrent.*;
import java.util.regex.*;

public class Solution {

    // Complete the kangaroo function below.
    static String kangaroo(int x1, int v1, int x2, int v2) {
        //                      0        3      4       2
        int i=1;
        while(!(((x2>x1)&&(v2>v1))||((x1>x2)&&(v1>v2)))){
            v1 = v1*i;
            v2 = v2*i;

            if((x1+v1)==(x2+v2)){
                System.out.print("YES");
                return "YES";

            }
            i++;
        }
        System.out.print("NO");
        return "NO";
    }

    private static final Scanner scanner = new Scanner(System.in);

    public static void main(String[] args) throws IOException {
        BufferedWriter bufferedWriter = new BufferedWriter(new FileWriter(System.getenv("OUTPUT_PATH")));

        String[] x1V1X2V2 = scanner.nextLine().split(" ");

        int x1 = Integer.parseInt(x1V1X2V2[0]);

        int v1 = Integer.parseInt(x1V1X2V2[1]);

        int x2 = Integer.parseInt(x1V1X2V2[2]);

        int v2 = Integer.parseInt(x1V1X2V2[3]);

        String result = kangaroo(x1, v1, x2, v2);

        bufferedWriter.write(result);
        bufferedWriter.newLine();

        bufferedWriter.close();

        scanner.close();
    }
}