#include <iostream>
#include <algorithm>
#include <iomanip>
#include <vector>
#include <queue>
#include <set>
#include <map>

using namespace std;
typedef long long ll;
int A[100];
int N;
ll X;
vector<ll> large, small;
int th = 100000; 
set<int> st, buf;
int pre[3000000];
int idx[3000000];

map<ll, vector<int>> idx_map;

int main(){
    ios::sync_with_stdio(false);
    cin.tie(0);
    cout << setprecision(10) << fixed;
    cin >> N >> X;
    for(int i = 0; i < N; i++){
        cin >> A[i];
        if(A[i] >= th) large.push_back(A[i]);
        else small.push_back(A[i]);
        idx_map[A[i]].push_back(i);
    }
    buf.insert(0);
    st.insert(0);
    sort(small.begin(), small.end());
    for(int i = 0; i < small.size(); i++){
        int m = small[i];
        vector<int> v;
        for(int n : buf){
            st.insert(n+m);
            pre[n+m] = n;
            idx[n+m] = i;
            v.push_back(n+m);
        }
        for(int n : v){
            buf.insert(n);
        }
    }
    int sz = large.size();
    for(int i = 0; i < (1<<sz); i++){
        ll sum = 0;
        for(int j = 0; j < sz; j++){
            int m = 1<<j;
            if(i&m){
                sum += large[j];
            }
        }
        if(st.count(X-sum) != 0){
            ll cur = X-sum;
            set<int> used_idx;
            while(cur != 0){
                int d = cur-pre[cur];
                int sz = idx_map[d].size();
                used_idx.insert(idx_map[d][sz-1]);
                idx_map[d].pop_back();
                cur = pre[cur];
            }
            for(int j = 0; j < sz; j++){
                int m = 1<<j;
                if(i&m){
                    int sz = idx_map[large[j]].size();
                    used_idx.insert(idx_map[large[j]][sz-1]);
                    idx_map[large[j]].pop_back();
                }
            }
            for(int j = 0; j < N; j++){
                if(used_idx.count(j) == 0) cout << 'x';
                else cout << 'o';
            }
            cout << endl;
            return 0;
        }
    }
    cout << "No" << endl;
}