#include "bits/stdc++.h"
using namespace std;
typedef long long ll;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;
const int INF = 1e9;
const ll LINF = 1e18;
inline ll gcd(ll a, ll b) { return b ? gcd(b, a%b) : a; }
inline ll lcm(ll a, ll b) { return a / gcd(a, b)*b; }
template<class S,class T> ostream& operator << (ostream& out,const pair<S,T>& o){ out << "(" << o.first << "," << o.second << ")"; return out; }
template<class T> ostream& operator << (ostream& out,const vector<T> V){ for(int i = 0; i < V.size(); i++){ out << V[i]; if(i!=V.size()-1) out << " ";} return out; }
template<class T> ostream& operator << (ostream& out,const vector<vector<T> > Mat){ for(int i = 0; i < Mat.size(); i++) { if(i != 0) out << endl; out << Mat[i];} return out; }
template<class S,class T> ostream& operator << (ostream& out,const map<S,T> mp){ out << "{ "; for(auto it = mp.begin(); it != mp.end(); it++){ out << it->first << ":" << it->second; if(mp.size()-1 != distance(mp.begin(),it)) out << ", "; } out << " }"; return out; }

/*
 <url:https://yukicoder.me/problems/no/332>
 問題文============================================================
 =================================================================
 解説=============================================================
 ================================================================
 */


vector<ll> ok_idx;
bool rec(ll n,ll X,map<pll,bool>& mp,vector<ll>& A){
    if(X==0){
        return true;
    }
    for(ll next = n-1; next >= -1; next--){
        if(mp.count(pll(next,X-A[n]))){
            if(rec(next,X-A[n],mp,A)){
                ok_idx.push_back(n);
                return true;
            }
        }
    }
    return false;
}
string solve(){
    string res;
    ll N,X; cin >> N >> X;
    vector<ll> A(N); for(auto& in:A) cin >> in;
    map<pll,bool> mp[2]; mp[0][pll(-1,0)] = true;
    int cur = 0,next = 1;
    for(int i = 0; i < N;i++){
        for(auto p:mp[cur]){
            mp[next][p.first] = true;
            mp[next][pll(i,p.first.second+A[i])] = true;
        }
        mp[cur].clear();
        swap(cur,next);
    }
    ll idx = -1;
    for(int i = 0; i < N;i++){
        if(mp[cur].count(pll(i,X))){
            idx = i;
        }
    }
    if(idx == -1) return "No";
    rec(idx,X,mp[cur],A);
    sort(ok_idx.begin(),ok_idx.end());
    res = string(N,'x');
    for(auto id:ok_idx) res[id] = 'o';
    return res;
}
int main(void) {
    cin.tie(0); ios_base::sync_with_stdio(false);
    cout << solve() << endl;
    return 0;
}