import java.util.*;

public class Main {
    public static void main(String[] args) throws Exception {
        // 標準入力から取得
        Scanner scan = new Scanner(System.in);
        // 取得した文字を格納する可変長リスト
        ArrayList<String> scList = new ArrayList<>();
        
        for (int i = 0; i >= 0; i++) {
            try {
                // 可変長リストに標準入力の値を格納
                scList.add(scan.nextLine());
            } catch (Exception e) {
                break;
            }
        }
        
        String[] numlist = scList.get(0).split(" ");
        
        int numA = Integer.parseInt(numlist[0]);
        int numB = Integer.parseInt(numlist[1]);
        int numC = Integer.parseInt(numlist[2]);
        int numD = Integer.parseInt(numlist[3]);
        
        for (int i = 0; i >= 0; i++) {
            numC = numC - numB;
            if(numC <= 0) {
                System.out.println("Yes");
                break;
            }
            numA = numA - numD;
            if (numA <= 0) {
                System.out.println("No");
                break;
            } 
        } 
    }
} import java.util.*; util.* java public class Main {
    public static void main(String[] args) throws Exception {
        // 標準入力から取得
        Scanner scan = new Scanner(System.in);
        // 取得した文字を格納する可変長リスト
        ArrayList<String> scList = new ArrayList<>();
        
        for (int i = 0; i >= 0; i++) {
            try {
                // 可変長リストに標準入力の値を格納
                scList.add(scan.nextLine());
            } catch (Exception e) {
                break;
            }
        }
        
        String[] numlist = scList.get(0).split(" ");
        
        int numA = Integer.parseInt(numlist[0]);
        int numB = Integer.parseInt(numlist[1]);
        int numC = Integer.parseInt(numlist[2]);
        int numD = Integer.parseInt(numlist[3]);
        
        for (int i = 0; i >= 0; i++) {
            numC = numC - numB;
            if(numC <= 0) {
                System.out.println("Yes");
                break;
            }
            numA = numA - numD;
            if (numA <= 0) {
                System.out.println("No");
                break;
            } 
        } 
    }
} Main public static void main(String[] args) throws Exception {
        // 標準入力から取得
        Scanner scan = new Scanner(System.in);
        // 取得した文字を格納する可変長リスト
        ArrayList<String> scList = new ArrayList<>();
        
        for (int i = 0; i >= 0; i++) {
            try {
                // 可変長リストに標準入力の値を格納
                scList.add(scan.nextLine());
            } catch (Exception e) {
                break;
            }
        }
        
        String[] numlist = scList.get(0).split(" ");
        
        int numA = Integer.parseInt(numlist[0]);
        int numB = Integer.parseInt(numlist[1]);
        int numC = Integer.parseInt(numlist[2]);
        int numD = Integer.parseInt(numlist[3]);
        
        for (int i = 0; i >= 0; i++) {
            numC = numC - numB;
            if(numC <= 0) {
                System.out.println("Yes");
                break;
            }
            numA = numA - numD;
            if (numA <= 0) {
                System.out.println("No");
                break;
            } 
        } 
    } main {
        // 標準入力から取得
        Scanner scan = new Scanner(System.in);
        // 取得した文字を格納する可変長リスト
        ArrayList<String> scList = new ArrayList<>();
        
        for (int i = 0; i >= 0; i++) {
            try {
                // 可変長リストに標準入力の値を格納
                scList.add(scan.nextLine());
            } catch (Exception e) {
                break;
            }
        }
        
        String[] numlist = scList.get(0).split(" ");
        
        int numA = Integer.parseInt(numlist[0]);
        int numB = Integer.parseInt(numlist[1]);
        int numC = Integer.parseInt(numlist[2]);
        int numD = Integer.parseInt(numlist[3]);
        
        for (int i = 0; i >= 0; i++) {
            numC = numC - numB;
            if(numC <= 0) {
                System.out.println("Yes");
                break;
            }
            numA = numA - numD;
            if (numA <= 0) {
                System.out.println("No");
                break;
            } 
        } 
    } Scanner scan = new Scanner(System.in); scan new Scanner(System.in) ArrayList<String> scList = new ArrayList<>(); scList new ArrayList<>() for (int i = 0; i >= 0; i++) {
            try {
                // 可変長リストに標準入力の値を格納
                scList.add(scan.nextLine());
            } catch (Exception e) {
                break;
            }
        } int i = 0; int i = 0; i 0 i >= 0 i 0 i++ i++ i {
            try {
                // 可変長リストに標準入力の値を格納
                scList.add(scan.nextLine());
            } catch (Exception e) {
                break;
            }
        } {
            try {
                // 可変長リストに標準入力の値を格納
                scList.add(scan.nextLine());
            } catch (Exception e) {
                break;
            }
        } try {
                // 可変長リストに標準入力の値を格納
                scList.add(scan.nextLine());
            } catch (Exception e) {
                break;
            } catch (Exception e) {
                break;
            } Exception e {
                break;
            } break; {
                // 可変長リストに標準入力の値を格納
                scList.add(scan.nextLine());
            } scList.add(scan.nextLine()) scList.add scList scan.nextLine() scan.nextLine scan String[] numlist = scList.get(0).split(" "); numlist scList.get(0).split(" ") scList.get(0).split scList.get(0) scList.get scList 0 " " int numA = Integer.parseInt(numlist[0]); numA Integer.parseInt(numlist[0]) Integer.parseInt Integer numlist[0] numlist 0 int numB = Integer.parseInt(numlist[1]); numB Integer.parseInt(numlist[1]) Integer.parseInt Integer numlist[1] numlist 1 int numC = Integer.parseInt(numlist[2]); numC Integer.parseInt(numlist[2]) Integer.parseInt Integer numlist[2] numlist 2 int numD = Integer.parseInt(numlist[3]); numD Integer.parseInt(numlist[3]) Integer.parseInt Integer numlist[3] numlist 3 for (int i = 0; i >= 0; i++) {
            numC = numC - numB;
            if(numC <= 0) {
                System.out.println("Yes");
                break;
            }
            numA = numA - numD;
            if (numA <= 0) {
                System.out.println("No");
                break;
            } 
        } int i = 0; int i = 0; i 0 i >= 0 i 0 i++ i++ i {
            numC = numC - numB;
            if(numC <= 0) {
                System.out.println("Yes");
                break;
            }
            numA = numA - numD;
            if (numA <= 0) {
                System.out.println("No");
                break;
            } 
        } {
            numC = numC - numB;
            if(numC <= 0) {
                System.out.println("Yes");
                break;
            }
            numA = numA - numD;
            if (numA <= 0) {
                System.out.println("No");
                break;
            } 
        } numC = numC - numB numC numC - numB numC numB if(numC <= 0) {
                System.out.println("Yes");
                break;
            } numC <= 0 numC 0 {
                System.out.println("Yes");
                break;
            } System.out.println("Yes") System.out.println System.out System System.out "Yes" break; numA = numA - numD numA numA - numD numA numD if (numA <= 0) {
                System.out.println("No");
                break;
            } numA <= 0 numA 0 {
                System.out.println("No");
                break;
            } System.out.println("No") System.out.println System.out System System.out "No" break; String[] args args public class Main {
    public static void main(String[] args) throws Exception {
        // 標準入力から取得
        Scanner scan = new Scanner(System.in);
        // 取得した文字を格納する可変長リスト
        ArrayList<String> scList = new ArrayList<>();
        
        for (int i = 0; i >= 0; i++) {
            try {
                // 可変長リストに標準入力の値を格納
                scList.add(scan.nextLine());
            } catch (Exception e) {
                break;
            }
        }
        
        String[] numlist = scList.get(0).split(" ");
        
        int numA = Integer.parseInt(numlist[0]);
        int numB = Integer.parseInt(numlist[1]);
        int numC = Integer.parseInt(numlist[2]);
        int numD = Integer.parseInt(numlist[3]);
        
        for (int i = 0; i >= 0; i++) {
            numC = numC - numB;
            if(numC <= 0) {
                System.out.println("Yes");
                break;
            }
            numA = numA - numD;
            if (numA <= 0) {
                System.out.println("No");
                break;
            } 
        } 
    }
} public class Main {
    public static void main(String[] args) throws Exception {
        // 標準入力から取得
        Scanner scan = new Scanner(System.in);
        // 取得した文字を格納する可変長リスト
        ArrayList<String> scList = new ArrayList<>();
        
        for (int i = 0; i >= 0; i++) {
            try {
                // 可変長リストに標準入力の値を格納
                scList.add(scan.nextLine());
            } catch (Exception e) {
                break;
            }
        }
        
        String[] numlist = scList.get(0).split(" ");
        
        int numA = Integer.parseInt(numlist[0]);
        int numB = Integer.parseInt(numlist[1]);
        int numC = Integer.parseInt(numlist[2]);
        int numD = Integer.parseInt(numlist[3]);
        
        for (int i = 0; i >= 0; i++) {
            numC = numC - numB;
            if(numC <= 0) {
                System.out.println("Yes");
                break;
            }
            numA = numA - numD;
            if (numA <= 0) {
                System.out.println("No");
                break;
            } 
        } 
    }
} Main
import java.util.*;

public class Main {
    public static void main(String[] args) throws Exception {
        // 標準入力から取得
        Scanner scan = new Scanner(System.in);
        // 取得した文字を格納する可変長リスト
        ArrayList<String> scList = new ArrayList<>();
        
        for (int i = 0; i >= 0; i++) {
            try {
                // 可変長リストに標準入力の値を格納
                scList.add(scan.nextLine());
            } catch (Exception e) {
                break;
            }
        }
        
        String[] numlist = scList.get(0).split(" ");
        
        int numA = Integer.parseInt(numlist[0]);
        int numB = Integer.parseInt(numlist[1]);
        int numC = Integer.parseInt(numlist[2]);
        int numD = Integer.parseInt(numlist[3]);
        
        for (int i = 0; i >= 0; i++) {
            numC = numC - numB;
            if(numC <= 0) {
                System.out.println("Yes");
                break;
            }
            numA = numA - numD;
            if (numA <= 0) {
                System.out.println("No");
                break;
            } 
        } 
    }
}