using System;
using System.Collections;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Numerics;
using BI=System.Numerics.BigInteger;

class TEST{
	static void Main(){
		Sol mySol =new Sol();
		mySol.Solve();
	}
}

class Sol{
	public void Solve(){
		
		Dictionary<long,BI> dp=new Dictionary<long,BI>();
		dp.Add(0,0);;
		for(int i=0;i<N;i++){
			Dictionary<long,BI> nxt=new Dictionary<long,BI>();
			foreach(var k in dp.Keys){
				if(k>X)continue;
				if(!nxt.ContainsKey(k))nxt.Add(k,dp[k]);
				if(k+A[i]>X)continue;
				if(!nxt.ContainsKey(k+A[i])){
					nxt.Add(k+A[i],dp[k]|(((BI)1)<<i));
				}
			}
			if(nxt.ContainsKey(X)){
				char[] Ans =new char[N];
				for(int ii=0;ii<N;ii++){
					Ans[ii]='x';
					if(((nxt[X]>>ii)&1)==1)Ans[ii]='o';
				}
				Console.WriteLine(new String(Ans));
				return;
			}
			dp=nxt;
		}
		
		Console.WriteLine("No");
		
		
		
		
		
		
		
		
		
	}
	long[] A;
	int N;
	long X;
	public Sol(){
		var d=rla();
		N=(int)d[0];
		X=d[1];
		A=rla();
	}




	static String rs(){return Console.ReadLine();}
	static int ri(){return int.Parse(Console.ReadLine());}
	static long rl(){return long.Parse(Console.ReadLine());}
	static double rd(){return double.Parse(Console.ReadLine());}
	static String[] rsa(){return Console.ReadLine().Split(' ');}
	static int[] ria(){return Array.ConvertAll(Console.ReadLine().Split(' '),e=>int.Parse(e));}
	static long[] rla(){return Array.ConvertAll(Console.ReadLine().Split(' '),e=>long.Parse(e));}
	static double[] rda(){return Array.ConvertAll(Console.ReadLine().Split(' '),e=>double.Parse(e));}
}