#include <bits/stdc++.h>

using namespace std;

typedef __uint128_t ll;
typedef vector<int> vi;
typedef vector<ll> vl;
typedef complex<double> P;
typedef pair<int,int> pii;
#define REP(i,n) for(ll i=0;i<n;++i)
#define REPR(i,n) for(ll i=1;i<n;++i)
#define FOR(i,a,b) for(ll i=a;i<b;++i)

#define DEBUG(x) cout<<#x<<": "<<x<<endl
#define DEBUG_VEC(v) cout<<#v<<":";REP(i,v.size())cout<<" "<<v[i];cout<<endl
#define ALL(a) (a).begin(),(a).end()

#define MOD (ll)(1e9+7)
#define ADD(a,b) a=((a)+(b))%MOD
#define FIX(a) ((a)%MOD+MOD)%MOD

ostream& operator<<(ostream& s,ll value){
  string out = "";
  if(value==0){
    out = "0";
  }else{
    while(value){
      out = (char)(value%10+'0') + out;
      value /= 10;
    }
  }
  s << out;
  return s;
}

istream& operator>>(istream& s,ll& value){
  string in = "";
  s >> in;
  if(in.size()>12){
    value = 1e13;
  }
  value = 0;
  REP(i,in.size()){
    value *= 10;
    value += in[i]-'0';
  }
  return s;
}

int main(){
  ll n,x;
  cin>>n>>x;
  vl a(n);
  REP(i,n)cin>>a[i];

  // 先頭20個を別扱いにする解法

  vl b = a;
  sort(ALL(b),greater<ll>());
  vl c,d;
  ll dsz = min<int>(20,n);
  ll csz = n-dsz;
  ll st = 0;
  while(st<n && d.size()!=dsz){
    if(b[st]>x){
      ++st;
      continue;
    }
    d.push_back(b[st]);
    ++st;
  }
  FOR(i,st,n)c.push_back(b[i]);

  // ナップサック
  ll cmax = 0;
  REP(i,csz)cmax += c[i];
  cmax = min(cmax,x);
  vector< vector<bool> > dp(csz+1,vector<bool>(cmax+1,false));
  vector< vector<bool> > pred(csz+1,vector<bool>(cmax+1,false));
  dp[0][0] = true;
  REP(i,csz){
    ll cost = c[i];
    REP(p,cmax+1){
      if(!dp[i][p])continue;
      dp[i+1][p] = true;
      pred[i+1][p] = false;
      if(p+cost<=cmax){
        dp[i+1][p+cost] = true;
        pred[i+1][p+cost] = true;
      }
    }
  }

  // 大きい値の全探索
  map<ll,ll> XS;
  REP(mask,1<<dsz){
    ll s = 0;
    REP(i,dsz) if(mask>>i&1) s+=d[i];
    if(s>x)continue;
    XS[s] = mask;
  }

  // 合体
  ll ansid = -1;
  REP(i,cmax+1){
    if(dp[csz][i]&&XS.count(x-i)){
      ansid = i;
      break;
    }
  }

  if(ansid==-1){
    cout << "No" << endl;
    return 0;
  }

  // 復元
  multiset<ll> result; // ここに使う値をぶっこんでいく

  // dp,predから
  ll cst = ansid;
  REP(_i,csz){
    ll i = csz-_i;
    if(pred[i][cst]){
      result.insert(c[i-1]);
      cst -= c[i-1];
    }
  }
  assert(cst==0);

  // 全探索のmaskから
  ll mask = XS[x-ansid];
  REP(i,dsz){
    if(mask>>i&1)result.insert(d[i]);
  }

  // 出力
  multiset<ll>::iterator iter;
  REP(i,n){
    iter = result.find(a[i]);
    if(iter!=result.end()){
      cout<<"o";
      result.erase(iter);
    }else{
      cout<<"x";
    }
  }
  cout<<endl;

  return 0;
}