import java.util.Scanner;
 
public class Main{
 
    public static void main(String args[]){
 
        Scanner scan = new Scanner(System.in);
        String s = scan.next();
 
        if(s.charAt(0)==s.charAt(1)){
            if(s.charAt(0) != s.charAt(2) && s.charAt(0) != s.charAt(3) && s.charAt(2) == s.charAt(3)){
                System.out.println("Yes");   
            }else{
                System.out.println("No");   
            }
        }else{
            if(s.charAt(0) == s.charAt(2)){
                if(s.charAt(1) == s.charAt(3)){
                    System.out.println("Yes");
                }else{
                    System.out.println("No");
                }
            }else if(s.charAt(0) == s.charAt(3)){
                if(s.charAt(1) == s.charAt(2)){
                    System.out.println("Yes");
                }else{
                    System.out.println("No");
                }
            }else{
                System.out.println("No");
            }
        }
    }
} import java.util.Scanner; Scanner java.util public class Main{
 
    public static void main(String args[]){
 
        Scanner scan = new Scanner(System.in);
        String s = scan.next();
 
        if(s.charAt(0)==s.charAt(1)){
            if(s.charAt(0) != s.charAt(2) && s.charAt(0) != s.charAt(3) && s.charAt(2) == s.charAt(3)){
                System.out.println("Yes");   
            }else{
                System.out.println("No");   
            }
        }else{
            if(s.charAt(0) == s.charAt(2)){
                if(s.charAt(1) == s.charAt(3)){
                    System.out.println("Yes");
                }else{
                    System.out.println("No");
                }
            }else if(s.charAt(0) == s.charAt(3)){
                if(s.charAt(1) == s.charAt(2)){
                    System.out.println("Yes");
                }else{
                    System.out.println("No");
                }
            }else{
                System.out.println("No");
            }
        }
    }
} Main public static void main(String args[]){
 
        Scanner scan = new Scanner(System.in);
        String s = scan.next();
 
        if(s.charAt(0)==s.charAt(1)){
            if(s.charAt(0) != s.charAt(2) && s.charAt(0) != s.charAt(3) && s.charAt(2) == s.charAt(3)){
                System.out.println("Yes");   
            }else{
                System.out.println("No");   
            }
        }else{
            if(s.charAt(0) == s.charAt(2)){
                if(s.charAt(1) == s.charAt(3)){
                    System.out.println("Yes");
                }else{
                    System.out.println("No");
                }
            }else if(s.charAt(0) == s.charAt(3)){
                if(s.charAt(1) == s.charAt(2)){
                    System.out.println("Yes");
                }else{
                    System.out.println("No");
                }
            }else{
                System.out.println("No");
            }
        }
    } main {
 
        Scanner scan = new Scanner(System.in);
        String s = scan.next();
 
        if(s.charAt(0)==s.charAt(1)){
            if(s.charAt(0) != s.charAt(2) && s.charAt(0) != s.charAt(3) && s.charAt(2) == s.charAt(3)){
                System.out.println("Yes");   
            }else{
                System.out.println("No");   
            }
        }else{
            if(s.charAt(0) == s.charAt(2)){
                if(s.charAt(1) == s.charAt(3)){
                    System.out.println("Yes");
                }else{
                    System.out.println("No");
                }
            }else if(s.charAt(0) == s.charAt(3)){
                if(s.charAt(1) == s.charAt(2)){
                    System.out.println("Yes");
                }else{
                    System.out.println("No");
                }
            }else{
                System.out.println("No");
            }
        }
    } Scanner scan = new Scanner(System.in); scan new Scanner(System.in) String s = scan.next(); s scan.next() scan.next scan if(s.charAt(0)==s.charAt(1)){
            if(s.charAt(0) != s.charAt(2) && s.charAt(0) != s.charAt(3) && s.charAt(2) == s.charAt(3)){
                System.out.println("Yes");   
            }else{
                System.out.println("No");   
            }
        }else{
            if(s.charAt(0) == s.charAt(2)){
                if(s.charAt(1) == s.charAt(3)){
                    System.out.println("Yes");
                }else{
                    System.out.println("No");
                }
            }else if(s.charAt(0) == s.charAt(3)){
                if(s.charAt(1) == s.charAt(2)){
                    System.out.println("Yes");
                }else{
                    System.out.println("No");
                }
            }else{
                System.out.println("No");
            }
        } s.charAt(0)==s.charAt(1) s.charAt(0) s.charAt s 0 s.charAt(1) s.charAt s 1 {
            if(s.charAt(0) != s.charAt(2) && s.charAt(0) != s.charAt(3) && s.charAt(2) == s.charAt(3)){
                System.out.println("Yes");   
            }else{
                System.out.println("No");   
            }
        } if(s.charAt(0) != s.charAt(2) && s.charAt(0) != s.charAt(3) && s.charAt(2) == s.charAt(3)){
                System.out.println("Yes");   
            }else{
                System.out.println("No");   
            } s.charAt(0) != s.charAt(2) && s.charAt(0) != s.charAt(3) && s.charAt(2) == s.charAt(3) s.charAt(0) != s.charAt(2) && s.charAt(0) != s.charAt(3) && s.charAt(2) == s.charAt(3) s.charAt(0) != s.charAt(2) s.charAt(0) s.charAt s 0 s.charAt(2) s.charAt s 2 s.charAt(0) != s.charAt(3) s.charAt(0) s.charAt s 0 s.charAt(3) s.charAt s 3 s.charAt(2) == s.charAt(3) s.charAt(2) s.charAt s 2 s.charAt(3) s.charAt s 3 {
                System.out.println("Yes");   
            } System.out.println("Yes") System.out.println System.out System System.out "Yes" {
                System.out.println("No");   
            } System.out.println("No") System.out.println System.out System System.out "No" {
            if(s.charAt(0) == s.charAt(2)){
                if(s.charAt(1) == s.charAt(3)){
                    System.out.println("Yes");
                }else{
                    System.out.println("No");
                }
            }else if(s.charAt(0) == s.charAt(3)){
                if(s.charAt(1) == s.charAt(2)){
                    System.out.println("Yes");
                }else{
                    System.out.println("No");
                }
            }else{
                System.out.println("No");
            }
        } if(s.charAt(0) == s.charAt(2)){
                if(s.charAt(1) == s.charAt(3)){
                    System.out.println("Yes");
                }else{
                    System.out.println("No");
                }
            }else if(s.charAt(0) == s.charAt(3)){
                if(s.charAt(1) == s.charAt(2)){
                    System.out.println("Yes");
                }else{
                    System.out.println("No");
                }
            }else{
                System.out.println("No");
            } s.charAt(0) == s.charAt(2) s.charAt(0) s.charAt s 0 s.charAt(2) s.charAt s 2 {
                if(s.charAt(1) == s.charAt(3)){
                    System.out.println("Yes");
                }else{
                    System.out.println("No");
                }
            } if(s.charAt(1) == s.charAt(3)){
                    System.out.println("Yes");
                }else{
                    System.out.println("No");
                } s.charAt(1) == s.charAt(3) s.charAt(1) s.charAt s 1 s.charAt(3) s.charAt s 3 {
                    System.out.println("Yes");
                } System.out.println("Yes") System.out.println System.out System System.out "Yes" {
                    System.out.println("No");
                } System.out.println("No") System.out.println System.out System System.out "No" if(s.charAt(0) == s.charAt(3)){
                if(s.charAt(1) == s.charAt(2)){
                    System.out.println("Yes");
                }else{
                    System.out.println("No");
                }
            }else{
                System.out.println("No");
            } s.charAt(0) == s.charAt(3) s.charAt(0) s.charAt s 0 s.charAt(3) s.charAt s 3 {
                if(s.charAt(1) == s.charAt(2)){
                    System.out.println("Yes");
                }else{
                    System.out.println("No");
                }
            } if(s.charAt(1) == s.charAt(2)){
                    System.out.println("Yes");
                }else{
                    System.out.println("No");
                } s.charAt(1) == s.charAt(2) s.charAt(1) s.charAt s 1 s.charAt(2) s.charAt s 2 {
                    System.out.println("Yes");
                } System.out.println("Yes") System.out.println System.out System System.out "Yes" {
                    System.out.println("No");
                } System.out.println("No") System.out.println System.out System System.out "No" {
                System.out.println("No");
            } System.out.println("No") System.out.println System.out System System.out "No" String args[] args public class Main{
 
    public static void main(String args[]){
 
        Scanner scan = new Scanner(System.in);
        String s = scan.next();
 
        if(s.charAt(0)==s.charAt(1)){
            if(s.charAt(0) != s.charAt(2) && s.charAt(0) != s.charAt(3) && s.charAt(2) == s.charAt(3)){
                System.out.println("Yes");   
            }else{
                System.out.println("No");   
            }
        }else{
            if(s.charAt(0) == s.charAt(2)){
                if(s.charAt(1) == s.charAt(3)){
                    System.out.println("Yes");
                }else{
                    System.out.println("No");
                }
            }else if(s.charAt(0) == s.charAt(3)){
                if(s.charAt(1) == s.charAt(2)){
                    System.out.println("Yes");
                }else{
                    System.out.println("No");
                }
            }else{
                System.out.println("No");
            }
        }
    }
} public class Main{
 
    public static void main(String args[]){
 
        Scanner scan = new Scanner(System.in);
        String s = scan.next();
 
        if(s.charAt(0)==s.charAt(1)){
            if(s.charAt(0) != s.charAt(2) && s.charAt(0) != s.charAt(3) && s.charAt(2) == s.charAt(3)){
                System.out.println("Yes");   
            }else{
                System.out.println("No");   
            }
        }else{
            if(s.charAt(0) == s.charAt(2)){
                if(s.charAt(1) == s.charAt(3)){
                    System.out.println("Yes");
                }else{
                    System.out.println("No");
                }
            }else if(s.charAt(0) == s.charAt(3)){
                if(s.charAt(1) == s.charAt(2)){
                    System.out.println("Yes");
                }else{
                    System.out.println("No");
                }
            }else{
                System.out.println("No");
            }
        }
    }
} Main
import java.util.Scanner;
 
public class Main{
 
    public static void main(String args[]){
 
        Scanner scan = new Scanner(System.in);
        String s = scan.next();
 
        if(s.charAt(0)==s.charAt(1)){
            if(s.charAt(0) != s.charAt(2) && s.charAt(0) != s.charAt(3) && s.charAt(2) == s.charAt(3)){
                System.out.println("Yes");   
            }else{
                System.out.println("No");   
            }
        }else{
            if(s.charAt(0) == s.charAt(2)){
                if(s.charAt(1) == s.charAt(3)){
                    System.out.println("Yes");
                }else{
                    System.out.println("No");
                }
            }else if(s.charAt(0) == s.charAt(3)){
                if(s.charAt(1) == s.charAt(2)){
                    System.out.println("Yes");
                }else{
                    System.out.println("No");
                }
            }else{
                System.out.println("No");
            }
        }
    }
}