import java.util.Scanner;

public class Main {

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);

		String s = sc.next();
		char[] list = new char[4];
		int cntkind = 0;
		int checkidx = 0;
		int checkflg = 0;
		list = s.toCharArray();



		for (int i = 1; i < list.length; i++) {
			if (list[0] == list[i]) {
				cntkind++;
				checkidx = i;
			}
		}

		if (cntkind == 1) {
			if (checkidx == 1) {
				if (list[2] == list[3]) {
					checkflg = 1;
				}
			} else if (checkidx == 2) {
				if (list[1] == list[3]) {
					checkflg = 1;
				}
			} else if (checkidx == 3) {
				if (list[1] == list[2]) {
					checkflg = 1;
				}
			}
		}

		if (checkflg == 0) {
			System.out.println("No");
		} else {
			System.out.println("Yes");
		}

	}
} import java.util.Scanner; Scanner java.util public class Main {

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);

		String s = sc.next();
		char[] list = new char[4];
		int cntkind = 0;
		int checkidx = 0;
		int checkflg = 0;
		list = s.toCharArray();



		for (int i = 1; i < list.length; i++) {
			if (list[0] == list[i]) {
				cntkind++;
				checkidx = i;
			}
		}

		if (cntkind == 1) {
			if (checkidx == 1) {
				if (list[2] == list[3]) {
					checkflg = 1;
				}
			} else if (checkidx == 2) {
				if (list[1] == list[3]) {
					checkflg = 1;
				}
			} else if (checkidx == 3) {
				if (list[1] == list[2]) {
					checkflg = 1;
				}
			}
		}

		if (checkflg == 0) {
			System.out.println("No");
		} else {
			System.out.println("Yes");
		}

	}
} Main public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);

		String s = sc.next();
		char[] list = new char[4];
		int cntkind = 0;
		int checkidx = 0;
		int checkflg = 0;
		list = s.toCharArray();



		for (int i = 1; i < list.length; i++) {
			if (list[0] == list[i]) {
				cntkind++;
				checkidx = i;
			}
		}

		if (cntkind == 1) {
			if (checkidx == 1) {
				if (list[2] == list[3]) {
					checkflg = 1;
				}
			} else if (checkidx == 2) {
				if (list[1] == list[3]) {
					checkflg = 1;
				}
			} else if (checkidx == 3) {
				if (list[1] == list[2]) {
					checkflg = 1;
				}
			}
		}

		if (checkflg == 0) {
			System.out.println("No");
		} else {
			System.out.println("Yes");
		}

	} main {
		Scanner sc = new Scanner(System.in);

		String s = sc.next();
		char[] list = new char[4];
		int cntkind = 0;
		int checkidx = 0;
		int checkflg = 0;
		list = s.toCharArray();



		for (int i = 1; i < list.length; i++) {
			if (list[0] == list[i]) {
				cntkind++;
				checkidx = i;
			}
		}

		if (cntkind == 1) {
			if (checkidx == 1) {
				if (list[2] == list[3]) {
					checkflg = 1;
				}
			} else if (checkidx == 2) {
				if (list[1] == list[3]) {
					checkflg = 1;
				}
			} else if (checkidx == 3) {
				if (list[1] == list[2]) {
					checkflg = 1;
				}
			}
		}

		if (checkflg == 0) {
			System.out.println("No");
		} else {
			System.out.println("Yes");
		}

	} Scanner sc = new Scanner(System.in); sc new Scanner(System.in) String s = sc.next(); s sc.next() sc.next sc char[] list = new char[4]; list new char[4] 4 int cntkind = 0; cntkind 0 int checkidx = 0; checkidx 0 int checkflg = 0; checkflg 0 list = s.toCharArray() list s.toCharArray() s.toCharArray s for (int i = 1; i < list.length; i++) {
			if (list[0] == list[i]) {
				cntkind++;
				checkidx = i;
			}
		} int i = 1; int i = 1; i 1 i < list.length i list.length list list.length i++ i++ i {
			if (list[0] == list[i]) {
				cntkind++;
				checkidx = i;
			}
		} {
			if (list[0] == list[i]) {
				cntkind++;
				checkidx = i;
			}
		} if (list[0] == list[i]) {
				cntkind++;
				checkidx = i;
			} list[0] == list[i] list[0] list 0 list[i] list i {
				cntkind++;
				checkidx = i;
			} cntkind++ cntkind checkidx = i checkidx i if (cntkind == 1) {
			if (checkidx == 1) {
				if (list[2] == list[3]) {
					checkflg = 1;
				}
			} else if (checkidx == 2) {
				if (list[1] == list[3]) {
					checkflg = 1;
				}
			} else if (checkidx == 3) {
				if (list[1] == list[2]) {
					checkflg = 1;
				}
			}
		} cntkind == 1 cntkind 1 {
			if (checkidx == 1) {
				if (list[2] == list[3]) {
					checkflg = 1;
				}
			} else if (checkidx == 2) {
				if (list[1] == list[3]) {
					checkflg = 1;
				}
			} else if (checkidx == 3) {
				if (list[1] == list[2]) {
					checkflg = 1;
				}
			}
		} if (checkidx == 1) {
				if (list[2] == list[3]) {
					checkflg = 1;
				}
			} else if (checkidx == 2) {
				if (list[1] == list[3]) {
					checkflg = 1;
				}
			} else if (checkidx == 3) {
				if (list[1] == list[2]) {
					checkflg = 1;
				}
			} checkidx == 1 checkidx 1 {
				if (list[2] == list[3]) {
					checkflg = 1;
				}
			} if (list[2] == list[3]) {
					checkflg = 1;
				} list[2] == list[3] list[2] list 2 list[3] list 3 {
					checkflg = 1;
				} checkflg = 1 checkflg 1 if (checkidx == 2) {
				if (list[1] == list[3]) {
					checkflg = 1;
				}
			} else if (checkidx == 3) {
				if (list[1] == list[2]) {
					checkflg = 1;
				}
			} checkidx == 2 checkidx 2 {
				if (list[1] == list[3]) {
					checkflg = 1;
				}
			} if (list[1] == list[3]) {
					checkflg = 1;
				} list[1] == list[3] list[1] list 1 list[3] list 3 {
					checkflg = 1;
				} checkflg = 1 checkflg 1 if (checkidx == 3) {
				if (list[1] == list[2]) {
					checkflg = 1;
				}
			} checkidx == 3 checkidx 3 {
				if (list[1] == list[2]) {
					checkflg = 1;
				}
			} if (list[1] == list[2]) {
					checkflg = 1;
				} list[1] == list[2] list[1] list 1 list[2] list 2 {
					checkflg = 1;
				} checkflg = 1 checkflg 1 if (checkflg == 0) {
			System.out.println("No");
		} else {
			System.out.println("Yes");
		} checkflg == 0 checkflg 0 {
			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);

		String s = sc.next();
		char[] list = new char[4];
		int cntkind = 0;
		int checkidx = 0;
		int checkflg = 0;
		list = s.toCharArray();



		for (int i = 1; i < list.length; i++) {
			if (list[0] == list[i]) {
				cntkind++;
				checkidx = i;
			}
		}

		if (cntkind == 1) {
			if (checkidx == 1) {
				if (list[2] == list[3]) {
					checkflg = 1;
				}
			} else if (checkidx == 2) {
				if (list[1] == list[3]) {
					checkflg = 1;
				}
			} else if (checkidx == 3) {
				if (list[1] == list[2]) {
					checkflg = 1;
				}
			}
		}

		if (checkflg == 0) {
			System.out.println("No");
		} else {
			System.out.println("Yes");
		}

	}
} public class Main {

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);

		String s = sc.next();
		char[] list = new char[4];
		int cntkind = 0;
		int checkidx = 0;
		int checkflg = 0;
		list = s.toCharArray();



		for (int i = 1; i < list.length; i++) {
			if (list[0] == list[i]) {
				cntkind++;
				checkidx = i;
			}
		}

		if (cntkind == 1) {
			if (checkidx == 1) {
				if (list[2] == list[3]) {
					checkflg = 1;
				}
			} else if (checkidx == 2) {
				if (list[1] == list[3]) {
					checkflg = 1;
				}
			} else if (checkidx == 3) {
				if (list[1] == list[2]) {
					checkflg = 1;
				}
			}
		}

		if (checkflg == 0) {
			System.out.println("No");
		} else {
			System.out.println("Yes");
		}

	}
} Main
import java.util.Scanner;

public class Main {

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);

		String s = sc.next();
		char[] list = new char[4];
		int cntkind = 0;
		int checkidx = 0;
		int checkflg = 0;
		list = s.toCharArray();



		for (int i = 1; i < list.length; i++) {
			if (list[0] == list[i]) {
				cntkind++;
				checkidx = i;
			}
		}

		if (cntkind == 1) {
			if (checkidx == 1) {
				if (list[2] == list[3]) {
					checkflg = 1;
				}
			} else if (checkidx == 2) {
				if (list[1] == list[3]) {
					checkflg = 1;
				}
			} else if (checkidx == 3) {
				if (list[1] == list[2]) {
					checkflg = 1;
				}
			}
		}

		if (checkflg == 0) {
			System.out.println("No");
		} else {
			System.out.println("Yes");
		}

	}
}