import java.util.*;
public class main{
    public static void main(String[] args){
        Scanner sc=new Scanner(System.in);
        int n=sc.nextInt();
        if(n>0 || Character.isDigit(n)){
            int r=n+'A'-1;
            System.out.print((char)r);
        }
        else if((n>=27 && n<=52)){
            int c=(n-26);
            System.out.print(r.append((char)c));
        }
        else{
            System.out.print("Invalid input");
        }
    }
}