import java.io.IOException;
import java.util.*;

public class Preorder {

	int size;
	Integer[] lst;


	void solve(){
		Scanner in = new Scanner(System.in);
		int count = 0;	
		while(in.hasNextLine()){
		//while(cur>=0){
			ArrayList<Integer> values = new ArrayList<Integer>();
			int cur = 0;
			if (in.hasNextInt()){
				cur = in.nextInt();
			}else{
				return;
			}
			while(cur>=0){
				values.add(cur);
				cur = in.nextInt();
			}
			lst = new Integer[values.size()];
			lst = values.toArray(lst);
			count++;
			System.out.print("Case ");
			System.out.print(count);
			System.out.print(": ");
			if(search(0,values.size()-1)){
				System.out.println("yes");
			}
			else{
				System.out.println("no");
			}
			//cur = in.nextInt();
		}
		in.close();

	}

	boolean search(int start, int stop){
		if(stop-start<2){
			return true;
		}
		int first = lst[start];
		int larger=stop+1; //If there's no right subtree, this would be the 
		for(int i=start+1;i<=stop;i++){
			if(lst[i]>first){
				larger = i;
				break;
			} // to find the start of the right subtree
		}
		for(int k=larger; k<stop+1; k++){
			if(lst[k]<first) return false;
		}
		return search(start+1,larger-1) && search(larger,stop);
	}

	public static void main(String[] args){
		Preorder a = new Preorder();
		a.solve();
		
	}


}