//解復元いらなくないですか
#include <string>
#include <vector>
#include<iostream>
#include<cstdio>
#include<cstdlib>
#include<stack>
#include<queue>
#include<cmath>
#include<algorithm>
#include<functional>
#include<list>
#include<deque>
#include<bitset>
#include<set>
#include<map>
#include<unordered_map>
#include<cstring>
#include<sstream>
#include<complex>
#include<iomanip>
#include<numeric>
#define X first
#define Y second
#define pb push_back
#define rep(X,Y) for (int (X) = 0;(X) < (Y);++(X))
#define rrep(X,Y) for (int (X) = (Y)-1;(X) >=0;--(X))
#define repe(X,Y) for ((X) = 0;(X) < (Y);++(X))
#define peat(X,Y) for (;(X) < (Y);++(X))
#define all(X) (X).begin(),(X).end()
#define rall(X) (X).rbegin(),(X).rend()
#define eb emplace_back
#define UNIQUE(X) (X).erase(unique(all(X)),(X).end())

using namespace std;
typedef long long ll;
typedef pair<int,int> pii;
typedef pair<ll,ll> pll;
template<class T> using vv=vector<vector<T>>;
template<class T> ostream& operator<<(ostream &os, const vector<T> &t) {
os<<"{"; rep(i,t.size()) {os<<t[i]<<",";} os<<"}"<<endl; return os;}
template<class S, class T> ostream& operator<<(ostream &os, const pair<S,T> &t) { return os<<"("<<t.first<<","<<t.second<<")";}
const ll MOD=1e9+7;

#include<cassert>

int main(){
  ios_base::sync_with_stdio(false);
  cout<<fixed<<setprecision(0);
  ll n,x;
  cin>>n>>x;
  vector<pll> a(n);
  rep(i,n){
    cin>>a[i].X;
    a[i].Y=i;
  }
  vector<ll> inv(n);
  for(pll p:a) inv[p.Y]=p.X;
  sort(all(a));
  ll T=1e5,t=n;
  map<ll,ll> st[112];
  st[0][0]=-1;
  rep(i,n){
    if(a[i].X>=T){
      t=i; break;
    }
    st[i+1]=st[i];
    for(pll x:st[i])
      st[i+1][x.X+a[i].X]=a[i].Y;
  }

  rep(i,1<<(n-t)){
    ll sum=0;
    rep(j,n-t) if(i>>j&1) sum+=a[t+j].X;
    if(st[t].count(x-sum)){
      string str(n,'x');
      rep(j,n-t) if(i>>j&1) str[a[t+j].Y]='o';
      ll rem=x-sum;
      for(int d=t; d>=0; --d){
	d=st[d][rem];
	str[d]='o';
	rem-=inv[d];
      }
      cout<<str<<endl;
      return 0;
    }
  }
  cout<<"No"<<endl;
  return 0;
}