#include <bits/stdc++.h>
using namespace std;

typedef long long ll;
typedef vector< int > vi;
typedef vector< vi > vvi;
typedef vector< ll > vl;
typedef vector< vl > vvl;
typedef pair< int, int > pii;
typedef vector< pii > vp;
typedef vector< double > vd;
typedef vector< vd > vvd;
typedef vector< string > vs;

template< class T1, class T2 >
int upmin( T1 &x, T2 v ){
  if( x > v ){
    x = v;
    return 1;
  }
  return 0;
}

template< class T1, class T2 >
int upmax( T1 &x, T2 v ){
  if( x < v ){
    x = v;
    return 1;
  }
  return 0;
}

const int INF = 0x3f3f3f3f;

int N;
ll X;
vi A;

void init(){
  cin >> N >> X;
  A = vi( N );
  for( int i = 0; i < N; ++i ){
    cin >> A[ i ];
  }
}

map< int, queue< int > > val2original_pos;

set< pair< ll, int > > partial;
vvi dp;
vvi dc; // decision

int dp_max_sum;

void preprocess(){
  if( N <= 20 ){
    for( int s = 0; s < 1 << N; ++s ){
      ll sum = 0;
      for( int i = 0; i < N; ++i ){
        if( s & 1 << i ){
          sum += A[ i ];
        }
      }
      if( sum == X ){
        for( int i = 0; i < N; ++i ){
          cout << "xo"[ s >> i & 1 ];
        }
        cout << endl;
        exit( 0 );
      }
    }
    cout << "No" << endl;   
    exit( 0 );
  }
  for( int i = 0; i < A.size(); ++i ){
    val2original_pos[ A[ i ] ].emplace( i );
  }
  sort( A.begin(), A.end(), greater< int >() );
  for( int s = 0; s < 1 << 20; ++s ){
    ll sum = 0;
    for( int i = 0; i < 20; ++i ){
      if( s & 1 << i ){
        sum += A[ i ];
      }
    }
    partial.emplace( sum, s );
  }
  for( int i = 20; i < N; ++i ){
    dp_max_sum += A[ i ];
  }
  assert( dp_max_sum < ( int ) 1e5 );
  dp = dc = vvi( N - 20 + 1, vi( dp_max_sum + 1 ) );
  dp[ 0 ][ 0 ] = 1;
  for( int i = 0; i < N - 20; ++i ){
    for( int j = dp_max_sum - A[ 20 + i ]; j >= 0; --j ){
      if( not dp[ i ][ j ] ) continue;
      dp[ i + 1 ][ j + A[ 20 + i ] ] = dc[ i + 1 ][ j + A[ 20 + i ] ] = 1;
      dp[ i + 1 ][ j ] = 1; dc[ i + 1 ][ j ] = 0;
    }
  }
}

void solve(){
  for( int i = 0; i <= dp_max_sum; ++i ){
    if( not dp[ N - 20 ][ i ] ) continue;
    auto it = partial.lower_bound( make_pair( X - i, 0 ) );
    if( it == partial.end() or it->first != X - i ) continue;
    vector< char > ans( N, 'x' );
    for( int j = 0; j < 20; ++j ){
      ans[ val2original_pos[ A[ j ] ].front() ] = 'o';
      val2original_pos[ A[ j ] ].pop();
    }
    for( int j = N - 20, k = i; j > 0; --j ){
      if( dc[ j ][ k ] ){
        ans[ val2original_pos[ A[ 20 + j - 1 ] ].front() ] = 'o';
        val2original_pos[ A[ 20 + j - 1 ] ].pop();
        k -= A[ 20 + j - 1 ];
      }
    }
    for( int j = 0; j < N; ++j ){
      cout << ans[ j ];
    }
    cout << endl;
    exit( 0 );
  }
  cout << "No" << endl;
}

signed main(){
  ios::sync_with_stdio( 0 );
  init();
  preprocess();
  solve();
  return 0;
}