import java.io.BufferedReader;
import java.io.InputStreamReader;

public class Main {
	public static void main(String[] args) throws Exception {
		try {
			BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
			char[] s = br.readLine().toCharArray();
			for (int i = 0; i < s.length - 2; i++) {
				label:
				for (int j = i + 2; j < s.length; j++) {
					int[] blank = new int[26];
					for (int k = 0; k < i; k++) {
						if (s[k] != ' ') {
							blank[s[k] - 'a'] = 1;
						}
					}
					for (int k = j; k < s.length; k++) {
						if (s[k] != ' ') {
							blank[s[k] - 'a'] = 1;
						}
					}
					for (int k = i; k < j; k++) {
						if ((k - i) % 2 == 0) {
							if (s[k] == ' ' || blank[s[k] - 'a'] == 1) {
								continue label;
							} else {
								blank[s[k] - 'a'] = 2;
							}
						} else {
							if (s[k] != ' ') {
								if (blank[s[k] - 'a'] == 2) {
									continue label;
								} else {
									blank[s[k] - 'a'] = 1;
								}
							}
						}
					}
					System.out.println("Yes");
					return;
				}
			}
			System.out.println("NO");
		} catch (Exception e) {
			System.out.println("NO");
		}
	}
}