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

#undef _P
#define _P(...) (void)printf(__VA_ARGS__)
#define FORR(x,arr) for(auto&& x:arr)
#define FOR(i,a,b) for (int i = (a); i < (b); i++)
#define RFOR(i,a,b) for (int i = (b)-1; i >= (a); i--)
#define REP(i,n) for (int i = 0; i < (n); i++)
#define RREP(i,n) for (int i = (n)-1; i >= 0; i--)
#define ALL(x) (x).begin(), (x).end()
#define ITR(x,c) for(__typeof(c.begin()) x=c.begin();x!=c.end();x++)
#define RITR(x,c) for(__typeof(c.rbegin()) x=c.rbegin();x!=c.rend();x++)
#define BIT(n) (1LL<<(n))
#define SZ(x) ((int)(x).size())
typedef long long ll;
// -------------------------------------

int N;
ll X;
int A[100];
int O[100];

#define TH 20

void Main() {
  cin >> N >> X;
  ll ss=0;
  REP(i, N) {
    cin >> A[i];
    O[i] = A[i];
    ss += A[i];
  }

  sort(A, A+N);

  vector<int> B;
  REP(i, TH) {
    if (N-TH+i >= 0) {
      B.push_back(A[N-TH+i]);
      ss -= A[N-TH+i];
    }
  }
  int K = SZ(B);
  int M = N - K;

  int dp[M+1][ss+1];
  memset(dp, 0, sizeof(dp));
  dp[0][0] = 1;
  REP(i, M) {
    REP(j, ss) if (dp[i][j]) {
      dp[i+1][j] = 1;
      if (j+A[i] <= ss) dp[i+1][j+A[i]] = 1;
    }
  }

  REP(i, BIT(K)) {
    ll s = 0;
    REP(j, K) {
      if (i & BIT(j)) {
        s += B[j];
      }
    }
    ll x = X - s;
    if (x < 0) continue;
    //_P("%lld,%lld\n", s, x);
    if (x <= ss && dp[M][x]) {
      vector<int> ans;
      REP(j, K) {
        if (i & BIT(j)) {
          ans.push_back(B[j]);
        }
      }
      RREP(j, M) {
        if (dp[j][x-A[j]]) {
          ans.push_back(A[j]);
          x-=A[j];
        }
      }
      {
        string as;
        REP(j, N) as.append("x");
        FORR(a, ans) {
          REP(j, N) {
            if (as[j] == 'x' && O[j] == a) {
              as[j] = 'o';
              break;
            }
          }
        }
        cout << as << endl;
      }

      return;
    }
  }
  puts("No");
}
int main() {Main(); return 0; }