#include<bits/stdc++.h>
using namespace std;
#define rep(i,n) for(ll i=0;i<n;i++)
#define repl(i,l,r) for(ll i=(l);i<(r);i++)
#define per(i,n) for(ll i=(n)-1;i>=0;i--)
#define perl(i,r,l) for(ll i=r-1;i>=l;i--)
#define fi first
#define se second
#define pb push_back
#define ins insert
#define pqueue(x) priority_queue<x,vector<x>,greater<x>>
#define all(x) (x).begin(),(x).end()
#define CST(x) cout<<fixed<<setprecision(x)
#define rev(x) reverse(x);
using ll=long long;
using vl=vector<ll>;
using vvl=vector<vector<ll>>;
using pl=pair<ll,ll>;
using vpl=vector<pl>;
using vvpl=vector<vpl>;
const ll MOD=1000000007;
const ll MOD9=998244353;
const int inf=2e9+1;
const ll INF=4e18;
const ll dy[8]={-1,0,1,0,1,1,-1,-1};
const ll dx[8]={0,-1,0,1,1,-1,1,-1};
template <typename T> inline bool chmax(T &a, T b) {
  return ((a < b) ? (a = b, true) : (false));
}
template <typename T> inline bool chmin(T &a, T b) {
  return ((a > b) ? (a = b, true) : (false));
}


int main(){
  ll n,x;cin >> n >> x;
  vl v(n);rep(i,n)cin >> v[i];
  if(n<=20){
    rep(bit,1<<n){
      ll to=0;
      rep(i,n){
        if(bit>>i&1)to+=v[i];
      }
      if(to==x){
        rep(i,n){
          if(bit>>i&1)cout << 'o';
          else cout << 'x';
        }
        cout << endl;return 0;
      }
    }
    cout << "No" << endl;return 0;
  }
  vpl pls(n);
  rep(i,n)pls[i]={v[i],i};
  sort(all(pls));
  map<ll,vl> mp;
  mp[0]=vl(0);
  rep(i,n-20){
    map<ll,vl> nmp=mp;
    for(auto p:mp){
      p.second.push_back(pls[i].second);
      nmp[p.first+pls[i].first]=p.second;
    }
    swap(nmp,mp);
  }
  rep(bit,1<<20){
    ll to=0;
    rep(i,20){
      if(bit>>i&1)to+=pls[n-20+i].first;
    }
    if(x<to)continue;
    if(mp.count(x-to)){
      vl use=mp[x-to];
      rep(i,20){
        if(bit>>i&1)use.push_back(pls[n-20+i].second);
      }
      sort(all(use));
      rep(i,n){
        if(binary_search(all(use),i))cout << 'o';
        else cout << 'x';
      }
      cout << endl;return 0;
    }
  }
  cout << "No" << endl;
}