import java.util.*;

public class Main {
    public static void main(String[] args) throws Exception {
        // Your code here!
        Scanner sc = new Scanner(System.in);
        String str = sc.next();
        char[] c = str.toCharArray();
        
        boolean ok = false;
        if (c[0] == c[1] && c[2] == c[3] && c[0] != c[2]) {
            ok = true;
        } else if (c[0] == c[2] && c[1] == c[3] && c[0] != c[1]) {
            ok = true;
        } else if (c[0] == c[3] && c[1] == c[2] && c[0] != c[1]) {
            ok = true;
        }
        
        if (ok) {
            System.out.println("Yes");
        } else {
            System.out.println("No");
        }
    }
} import java.util.*; util.* java public class Main {
    public static void main(String[] args) throws Exception {
        // Your code here!
        Scanner sc = new Scanner(System.in);
        String str = sc.next();
        char[] c = str.toCharArray();
        
        boolean ok = false;
        if (c[0] == c[1] && c[2] == c[3] && c[0] != c[2]) {
            ok = true;
        } else if (c[0] == c[2] && c[1] == c[3] && c[0] != c[1]) {
            ok = true;
        } else if (c[0] == c[3] && c[1] == c[2] && c[0] != c[1]) {
            ok = true;
        }
        
        if (ok) {
            System.out.println("Yes");
        } else {
            System.out.println("No");
        }
    }
} Main public static void main(String[] args) throws Exception {
        // Your code here!
        Scanner sc = new Scanner(System.in);
        String str = sc.next();
        char[] c = str.toCharArray();
        
        boolean ok = false;
        if (c[0] == c[1] && c[2] == c[3] && c[0] != c[2]) {
            ok = true;
        } else if (c[0] == c[2] && c[1] == c[3] && c[0] != c[1]) {
            ok = true;
        } else if (c[0] == c[3] && c[1] == c[2] && c[0] != c[1]) {
            ok = true;
        }
        
        if (ok) {
            System.out.println("Yes");
        } else {
            System.out.println("No");
        }
    } main {
        // Your code here!
        Scanner sc = new Scanner(System.in);
        String str = sc.next();
        char[] c = str.toCharArray();
        
        boolean ok = false;
        if (c[0] == c[1] && c[2] == c[3] && c[0] != c[2]) {
            ok = true;
        } else if (c[0] == c[2] && c[1] == c[3] && c[0] != c[1]) {
            ok = true;
        } else if (c[0] == c[3] && c[1] == c[2] && c[0] != c[1]) {
            ok = true;
        }
        
        if (ok) {
            System.out.println("Yes");
        } else {
            System.out.println("No");
        }
    } Scanner sc = new Scanner(System.in); sc new Scanner(System.in) String str = sc.next(); str sc.next() sc.next sc char[] c = str.toCharArray(); c str.toCharArray() str.toCharArray str boolean ok = false; ok false if (c[0] == c[1] && c[2] == c[3] && c[0] != c[2]) {
            ok = true;
        } else if (c[0] == c[2] && c[1] == c[3] && c[0] != c[1]) {
            ok = true;
        } else if (c[0] == c[3] && c[1] == c[2] && c[0] != c[1]) {
            ok = true;
        } c[0] == c[1] && c[2] == c[3] && c[0] != c[2] c[0] == c[1] && c[2] == c[3] && c[0] != c[2] c[0] == c[1] c[0] c 0 c[1] c 1 c[2] == c[3] c[2] c 2 c[3] c 3 c[0] != c[2] c[0] c 0 c[2] c 2 {
            ok = true;
        } ok = true ok true if (c[0] == c[2] && c[1] == c[3] && c[0] != c[1]) {
            ok = true;
        } else if (c[0] == c[3] && c[1] == c[2] && c[0] != c[1]) {
            ok = true;
        } c[0] == c[2] && c[1] == c[3] && c[0] != c[1] c[0] == c[2] && c[1] == c[3] && c[0] != c[1] c[0] == c[2] c[0] c 0 c[2] c 2 c[1] == c[3] c[1] c 1 c[3] c 3 c[0] != c[1] c[0] c 0 c[1] c 1 {
            ok = true;
        } ok = true ok true if (c[0] == c[3] && c[1] == c[2] && c[0] != c[1]) {
            ok = true;
        } c[0] == c[3] && c[1] == c[2] && c[0] != c[1] c[0] == c[3] && c[1] == c[2] && c[0] != c[1] c[0] == c[3] c[0] c 0 c[3] c 3 c[1] == c[2] c[1] c 1 c[2] c 2 c[0] != c[1] c[0] c 0 c[1] c 1 {
            ok = true;
        } ok = true ok true if (ok) {
            System.out.println("Yes");
        } else {
            System.out.println("No");
        } ok {
            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" String[] args args public class Main {
    public static void main(String[] args) throws Exception {
        // Your code here!
        Scanner sc = new Scanner(System.in);
        String str = sc.next();
        char[] c = str.toCharArray();
        
        boolean ok = false;
        if (c[0] == c[1] && c[2] == c[3] && c[0] != c[2]) {
            ok = true;
        } else if (c[0] == c[2] && c[1] == c[3] && c[0] != c[1]) {
            ok = true;
        } else if (c[0] == c[3] && c[1] == c[2] && c[0] != c[1]) {
            ok = true;
        }
        
        if (ok) {
            System.out.println("Yes");
        } else {
            System.out.println("No");
        }
    }
} public class Main {
    public static void main(String[] args) throws Exception {
        // Your code here!
        Scanner sc = new Scanner(System.in);
        String str = sc.next();
        char[] c = str.toCharArray();
        
        boolean ok = false;
        if (c[0] == c[1] && c[2] == c[3] && c[0] != c[2]) {
            ok = true;
        } else if (c[0] == c[2] && c[1] == c[3] && c[0] != c[1]) {
            ok = true;
        } else if (c[0] == c[3] && c[1] == c[2] && c[0] != c[1]) {
            ok = true;
        }
        
        if (ok) {
            System.out.println("Yes");
        } else {
            System.out.println("No");
        }
    }
} Main
import java.util.*;

public class Main {
    public static void main(String[] args) throws Exception {
        // Your code here!
        Scanner sc = new Scanner(System.in);
        String str = sc.next();
        char[] c = str.toCharArray();
        
        boolean ok = false;
        if (c[0] == c[1] && c[2] == c[3] && c[0] != c[2]) {
            ok = true;
        } else if (c[0] == c[2] && c[1] == c[3] && c[0] != c[1]) {
            ok = true;
        } else if (c[0] == c[3] && c[1] == c[2] && c[0] != c[1]) {
            ok = true;
        }
        
        if (ok) {
            System.out.println("Yes");
        } else {
            System.out.println("No");
        }
    }
}