#include <bits/stdc++.h>

using namespace std;

//typedef
//------------------------------------------
typedef vector<int> VI;
typedef vector<VI> VVI;
typedef vector<string> VS;
typedef pair<int, int> PII;
typedef long long LL;

//container util
//------------------------------------------
#define ALL(a)  (a).begin(),(a).end()
#define RALL(a) (a).rbegin(), (a).rend()
#define PB push_back
#define MP make_pair
#define SZ(a) int((a).size())
#define EACH(i,c) for(typeof((c).begin()) i=(c).begin(); i!=(c).end(); ++i)
#define EXIST(s,e) ((s).find(e)!=(s).end())
#define SORT(c) sort((c).begin(),(c).end())

//repetition
//------------------------------------------
#define FOR(i,a,b) for(int i=(a);i<(b);++i)
#define REP(i,n)  FOR(i,0,n)

//constant
//--------------------------------------------
const double EPS = 1e-10;
const double PI  = acos(-1.0);

int main(){
  cin.tie(0);
  ios_base::sync_with_stdio(false);

  LL N, X; cin >> N >> X;
  map<LL,string> poi;
  REP(j,N){
	LL a; cin >> a;
	for(auto i=poi.rbegin();i!=poi.rend();++i){
	  string s = i->second;
	  poi[i->first+a] = s.replace(j, 1, "o");
	}
	poi[a] = string(N,'x').replace(j,1,"o");
  }

  if(!poi.count(X)) cout << "No" << endl;
  else cout << poi[X] << endl;
  
  return 0;
}