package yukikoda;

import java.util.Scanner;
public class Main {
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		char[] ch = new char[13];
		String str = sc.next();
		int count = 0;
		char[] alpha = {'a','b','c','d','e','f','g','h','i','j','k','l','m','n','o','p','q','r','s','t','u','v','w','x','y','z'};

		for(int i=0; i<ch.length; i++) {
			ch[i] = str.charAt(i);
		}

		for(int k=0; k<12; k++) {
			for(int m=k+1; m<13; m++) {
				if(ch[k] == ch[m] && ch[k] != '/' && ch[m] != '/') {
					for(int n=0; n<alpha.length; n++) {
						if(alpha[n] == ch[k]) {
							if(alpha[n] != '/') {
								count++;
								alpha[n] = '/';
							}
						}
					}
					ch[k] = '/';
					ch[m] = '/';
				}
			}
		}

		if(count == 6) {
			for(int l=0; l<13; l++) {
				if(ch[l] != '/') {
						System.out.print(ch[l]);
					}
				}
			}else {
				System.out.println("Impossible");
		}
	}
}