import java.util.*;

class Main{
  public static void main(String[] args){
    Scanner sc = new Scanner(System.in);
    //高橋君のモンスター
    int A = sc.nextInt(); //体力
    int B = sc.nextInt(); //攻撃力
    //青木君のモンスター
    int C = sc.nextInt(); //体力
    int D = sc.nextInt(); //攻撃力
    //高橋君→青木君→・・・と攻撃を繰り返す
    int count = 0;
    do{
      if (count % 2 == 0){
      	C = C - B;
        //System.out.println( "青木君の体力=" + C);
      }
      else{
        A = A - D;
        //System.out.println( "高橋君の体力=" + A);
      }
      count++ ;
    }while(A*C > 0);
    //高橋君が勝てばYes、青木君が勝てばNo.
    if (A <= 0)
      System.out.println("No");
    else{
     if (C <= 0) 
      System.out.println("Yes");
     else
       System.out.println("ERROR");
    }
    
  }
} import java.util.*; util.* java class Main{
  public static void main(String[] args){
    Scanner sc = new Scanner(System.in);
    //高橋君のモンスター
    int A = sc.nextInt(); //体力
    int B = sc.nextInt(); //攻撃力
    //青木君のモンスター
    int C = sc.nextInt(); //体力
    int D = sc.nextInt(); //攻撃力
    //高橋君→青木君→・・・と攻撃を繰り返す
    int count = 0;
    do{
      if (count % 2 == 0){
      	C = C - B;
        //System.out.println( "青木君の体力=" + C);
      }
      else{
        A = A - D;
        //System.out.println( "高橋君の体力=" + A);
      }
      count++ ;
    }while(A*C > 0);
    //高橋君が勝てばYes、青木君が勝てばNo.
    if (A <= 0)
      System.out.println("No");
    else{
     if (C <= 0) 
      System.out.println("Yes");
     else
       System.out.println("ERROR");
    }
    
  }
} Main public static void main(String[] args){
    Scanner sc = new Scanner(System.in);
    //高橋君のモンスター
    int A = sc.nextInt(); //体力
    int B = sc.nextInt(); //攻撃力
    //青木君のモンスター
    int C = sc.nextInt(); //体力
    int D = sc.nextInt(); //攻撃力
    //高橋君→青木君→・・・と攻撃を繰り返す
    int count = 0;
    do{
      if (count % 2 == 0){
      	C = C - B;
        //System.out.println( "青木君の体力=" + C);
      }
      else{
        A = A - D;
        //System.out.println( "高橋君の体力=" + A);
      }
      count++ ;
    }while(A*C > 0);
    //高橋君が勝てばYes、青木君が勝てばNo.
    if (A <= 0)
      System.out.println("No");
    else{
     if (C <= 0) 
      System.out.println("Yes");
     else
       System.out.println("ERROR");
    }
    
  } main {
    Scanner sc = new Scanner(System.in);
    //高橋君のモンスター
    int A = sc.nextInt(); //体力
    int B = sc.nextInt(); //攻撃力
    //青木君のモンスター
    int C = sc.nextInt(); //体力
    int D = sc.nextInt(); //攻撃力
    //高橋君→青木君→・・・と攻撃を繰り返す
    int count = 0;
    do{
      if (count % 2 == 0){
      	C = C - B;
        //System.out.println( "青木君の体力=" + C);
      }
      else{
        A = A - D;
        //System.out.println( "高橋君の体力=" + A);
      }
      count++ ;
    }while(A*C > 0);
    //高橋君が勝てばYes、青木君が勝てばNo.
    if (A <= 0)
      System.out.println("No");
    else{
     if (C <= 0) 
      System.out.println("Yes");
     else
       System.out.println("ERROR");
    }
    
  } Scanner sc = new Scanner(System.in); sc new Scanner(System.in) int A = sc.nextInt(); A sc.nextInt() sc.nextInt sc int B = sc.nextInt(); B sc.nextInt() sc.nextInt sc int C = sc.nextInt(); C sc.nextInt() sc.nextInt sc int D = sc.nextInt(); D sc.nextInt() sc.nextInt sc int count = 0; count 0 do{
      if (count % 2 == 0){
      	C = C - B;
        //System.out.println( "青木君の体力=" + C);
      }
      else{
        A = A - D;
        //System.out.println( "高橋君の体力=" + A);
      }
      count++ ;
    }while(A*C > 0); A*C > 0 A*C A C 0 {
      if (count % 2 == 0){
      	C = C - B;
        //System.out.println( "青木君の体力=" + C);
      }
      else{
        A = A - D;
        //System.out.println( "高橋君の体力=" + A);
      }
      count++ ;
    } if (count % 2 == 0){
      	C = C - B;
        //System.out.println( "青木君の体力=" + C);
      }
      else{
        A = A - D;
        //System.out.println( "高橋君の体力=" + A);
      } count % 2 == 0 count % 2 count 2 0 {
      	C = C - B;
        //System.out.println( "青木君の体力=" + C);
      } C = C - B C C - B C B {
        A = A - D;
        //System.out.println( "高橋君の体力=" + A);
      } A = A - D A A - D A D count++ count if (A <= 0)
      System.out.println("No");
    else{
     if (C <= 0) 
      System.out.println("Yes");
     else
       System.out.println("ERROR");
    } A <= 0 A 0 System.out.println("No") System.out.println System.out System System.out "No" {
     if (C <= 0) 
      System.out.println("Yes");
     else
       System.out.println("ERROR");
    } if (C <= 0) 
      System.out.println("Yes");
     else
       System.out.println("ERROR"); C <= 0 C 0 System.out.println("Yes") System.out.println System.out System System.out "Yes" System.out.println("ERROR") System.out.println System.out System System.out "ERROR" String[] args args
import java.util.*;

class Main{
  public static void main(String[] args){
    Scanner sc = new Scanner(System.in);
    //高橋君のモンスター
    int A = sc.nextInt(); //体力
    int B = sc.nextInt(); //攻撃力
    //青木君のモンスター
    int C = sc.nextInt(); //体力
    int D = sc.nextInt(); //攻撃力
    //高橋君→青木君→・・・と攻撃を繰り返す
    int count = 0;
    do{
      if (count % 2 == 0){
      	C = C - B;
        //System.out.println( "青木君の体力=" + C);
      }
      else{
        A = A - D;
        //System.out.println( "高橋君の体力=" + A);
      }
      count++ ;
    }while(A*C > 0);
    //高橋君が勝てばYes、青木君が勝てばNo.
    if (A <= 0)
      System.out.println("No");
    else{
     if (C <= 0) 
      System.out.println("Yes");
     else
       System.out.println("ERROR");
    }
    
  }
}