
import java.util.*;

public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int tLife = sc.nextInt();
        int tAttackk = sc.nextInt();
        int aLife = sc.nextInt();
        int aAttack = sc.nextInt();
        boolean flg = false;

        while (true) {
        	flg = false;
        	aLife -= tAttackk;
			if(aLife <= 0) {
				flg = true;
				break;
			}

			tLife -= aAttack;
			if(tLife <= 0) {
				break;
			}

		}
        if(!flg) {
        	System.out.println("No");
        }else {
			System.out.println("Yes");
		}
		}
}
 import java.util.*; util.* java public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int tLife = sc.nextInt();
        int tAttackk = sc.nextInt();
        int aLife = sc.nextInt();
        int aAttack = sc.nextInt();
        boolean flg = false;

        while (true) {
        	flg = false;
        	aLife -= tAttackk;
			if(aLife <= 0) {
				flg = true;
				break;
			}

			tLife -= aAttack;
			if(tLife <= 0) {
				break;
			}

		}
        if(!flg) {
        	System.out.println("No");
        }else {
			System.out.println("Yes");
		}
		}
} Main public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int tLife = sc.nextInt();
        int tAttackk = sc.nextInt();
        int aLife = sc.nextInt();
        int aAttack = sc.nextInt();
        boolean flg = false;

        while (true) {
        	flg = false;
        	aLife -= tAttackk;
			if(aLife <= 0) {
				flg = true;
				break;
			}

			tLife -= aAttack;
			if(tLife <= 0) {
				break;
			}

		}
        if(!flg) {
        	System.out.println("No");
        }else {
			System.out.println("Yes");
		}
		} main {
        Scanner sc = new Scanner(System.in);
        int tLife = sc.nextInt();
        int tAttackk = sc.nextInt();
        int aLife = sc.nextInt();
        int aAttack = sc.nextInt();
        boolean flg = false;

        while (true) {
        	flg = false;
        	aLife -= tAttackk;
			if(aLife <= 0) {
				flg = true;
				break;
			}

			tLife -= aAttack;
			if(tLife <= 0) {
				break;
			}

		}
        if(!flg) {
        	System.out.println("No");
        }else {
			System.out.println("Yes");
		}
		} Scanner sc = new Scanner(System.in); sc new Scanner(System.in) int tLife = sc.nextInt(); tLife sc.nextInt() sc.nextInt sc int tAttackk = sc.nextInt(); tAttackk sc.nextInt() sc.nextInt sc int aLife = sc.nextInt(); aLife sc.nextInt() sc.nextInt sc int aAttack = sc.nextInt(); aAttack sc.nextInt() sc.nextInt sc boolean flg = false; flg false while (true) {
        	flg = false;
        	aLife -= tAttackk;
			if(aLife <= 0) {
				flg = true;
				break;
			}

			tLife -= aAttack;
			if(tLife <= 0) {
				break;
			}

		} true {
        	flg = false;
        	aLife -= tAttackk;
			if(aLife <= 0) {
				flg = true;
				break;
			}

			tLife -= aAttack;
			if(tLife <= 0) {
				break;
			}

		} flg = false flg false aLife -= tAttackk aLife tAttackk if(aLife <= 0) {
				flg = true;
				break;
			} aLife <= 0 aLife 0 {
				flg = true;
				break;
			} flg = true flg true break; tLife -= aAttack tLife aAttack if(tLife <= 0) {
				break;
			} tLife <= 0 tLife 0 {
				break;
			} break; if(!flg) {
        	System.out.println("No");
        }else {
			System.out.println("Yes");
		} !flg flg {
        	System.out.println("No");
        } System.out.println("No") System.out.println System.out System System.out "No" {
			System.out.println("Yes");
		} System.out.println("Yes") System.out.println System.out System System.out "Yes" String[] args args public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int tLife = sc.nextInt();
        int tAttackk = sc.nextInt();
        int aLife = sc.nextInt();
        int aAttack = sc.nextInt();
        boolean flg = false;

        while (true) {
        	flg = false;
        	aLife -= tAttackk;
			if(aLife <= 0) {
				flg = true;
				break;
			}

			tLife -= aAttack;
			if(tLife <= 0) {
				break;
			}

		}
        if(!flg) {
        	System.out.println("No");
        }else {
			System.out.println("Yes");
		}
		}
} public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int tLife = sc.nextInt();
        int tAttackk = sc.nextInt();
        int aLife = sc.nextInt();
        int aAttack = sc.nextInt();
        boolean flg = false;

        while (true) {
        	flg = false;
        	aLife -= tAttackk;
			if(aLife <= 0) {
				flg = true;
				break;
			}

			tLife -= aAttack;
			if(tLife <= 0) {
				break;
			}

		}
        if(!flg) {
        	System.out.println("No");
        }else {
			System.out.println("Yes");
		}
		}
} Main

import java.util.*;

public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int tLife = sc.nextInt();
        int tAttackk = sc.nextInt();
        int aLife = sc.nextInt();
        int aAttack = sc.nextInt();
        boolean flg = false;

        while (true) {
        	flg = false;
        	aLife -= tAttackk;
			if(aLife <= 0) {
				flg = true;
				break;
			}

			tLife -= aAttack;
			if(tLife <= 0) {
				break;
			}

		}
        if(!flg) {
        	System.out.println("No");
        }else {
			System.out.println("Yes");
		}
		}
}

