package no332;

import java.util.ArrayList;
import java.util.Collections;
import java.util.Scanner;

public class Main {
	public static final int MAX = 10000;
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int n = sc.nextInt();
		long x = sc.nextLong();
		ArrayList<Pair> a = new ArrayList<>(); //i,a
		for(int i=0;i<n;i++) {
			int aa = sc.nextInt();
			a.add(new Pair(i,aa));
		}
		Collections.sort(a,(xx,yy)->Integer.compare(xx.a, yy.a));
		int n2 = 0;
		int max2 = 0;
		for(Pair p:a) {
			if (p.a <= MAX) {
				n2++;
				max2 += p.a;
			}else{
				break;
			}
		}
		boolean[][] dp = new boolean[n2+1][max2+1];
		dp[0][0] = true;
		for(int i=1;i<=n2;i++) {
			int w = a.get(i-1).a;
			for(int j=max2;j>=0;j--) {
				if (j >= w) {
					dp[i][j] |= dp[i-1][j-w];
				}
				dp[i][j] |= dp[i-1][j];
			}
		}
		int n3 = n - n2;
		for(int i=0;i<1<<n3;i++) {
			long sum = 0;
			for(int j=0;j<n3;j++) {
				if ((i>>j&1)>0) {
					sum += a.get(n2 + j).a;
				}
			}
			if (sum > x) {
				continue;
			}
			if (x - sum <= max2 && dp[n2][(int) (x-sum)]) {
				boolean[] ans = new boolean[n];
				for(int j=0;j<n3;j++) {
					if ((i>>j&1)>0) {
						ans[a.get(n2+j).i] = true;
					}
				}
				int now = (int) (x - sum);
				for(int i2=n2;i2>=1;i2--) {
					int w = a.get(i2-1).a;
					if (now >= w && dp[i2-1][now-w]) {
						ans[a.get(i2-1).i] = true;
						now -= w;
					}
				}
				StringBuilder sb = new StringBuilder();
				for(int j=0;j<n;j++) {
					sb.append(ans[j] ? 'o' : 'x');
				}
				System.out.println(sb);
				return;
			}
		}
		System.out.println("No");
	}

}
class Pair {
	int i,a;
	public Pair(int i,int a) {
		this.i = i;
		this.a = a;
	}
}