//Java
import java.util.*;

class uva10093{
	public static void main(String args[]){
		Scanner sc=new Scanner(System.in);
		String st;

		while(sc.hasNextLine()){
			st=sc.nextLine();

			char Ctemp[]=st.toCharArray();
			int sum=0;
			int max=1;
			for(char temp:Ctemp){
				int R=0;
				if(temp>=48 && temp<=57){
					R=temp-48;
				}else if(temp>=65 && temp<=90){
					R=temp-55;
				}else if(temp>=97 && temp<=122){
					R=temp-61;
				}
				sum=sum+R;
				if(R>max) max=R;
			}

			for(int i=max;i<=62;i++){
				if(i==62){
					System.out.println("such number is impossible!");
					break;
				}
				if(sum%i==0){
					System.out.println(i+1);
					break;
				}

			}
		}

	}
}