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

public class N548
{
	public static void main(String[] args) throws IOException
	{
		BufferedReader br=new BufferedReader(new InputStreamReader(System.in));
		String str=br.readLine();
		int imp=0;
		if(str.length()!=13){imp++;}
		char l='a';
		char ll=' ';
		int len =13;
		int[] buf=new int[len];
		int k=0;
		int db=0;
		char ans=0;
		int count=0;
		while(k<13)
		{
		for(int i=0;i<len;i++)
		{
			if(String.valueOf(l).equals(str.substring(i,i+1))){buf[k]++;count++;}
		}
		if(buf[k]>2){imp=1;k=k+100;}
		if(buf[k]==0){ans=l;}
		if(buf[k]==2){db++;}
		if(db==2){imp=1;k=k+100;}
		l++;k++;
		}
		imp=(count==13)?0:1;
		if(imp==0&&ans!=0)
		{System.out.println(ans);}
		if(imp==0&&ans==0)
		{
			l='a';
			for(int i=0;i<13;i++)
			{
				System.out.println(l);
				l++;
			}
		}
		if(imp==1){System.out.println("Impossible");}
	}
}