#include <bits/stdc++.h>
using namespace std;
#define GET_MACRO(a, b, c, NAME, ...) NAME
#define rep(...) GET_MACRO(__VA_ARGS__, rep3, rep2)(__VA_ARGS__)
#define rep2(i, a) rep3 (i, 0, a)
#define rep3(i, a, b) for (int i = (a); i < (b); i++)
#define repr(...) GET_MACRO(__VA_ARGS__, repr3, repr2)(__VA_ARGS__)
#define repr2(i, a) repr3 (i, 0, a)
#define repr3(i, a, b) for (int i = (b) - 1; i >= (a); i--)
template<class T1, class T2> inline bool chmin(T1 &a, T2 b) { return b < a && (a = b, true); }
template<class T1, class T2> inline bool chmax(T1 &a, T2 b) { return a < b && (a = b, true); }
using ll = long long;

const int N = 50505;

int main() {
	ll n, X;
	cin >> n >> X;
	vector<ll> a(n);
	rep (i, n) cin >> a[i];

	vector<pair<ll, ll>> ai(n);
	rep (i, n) ai[i] = {a[i], i};
	sort(ai.begin(), ai.end());
	rep (i, n) a[i] = ai[i].first;

	vector<ll> x, y;
	rep (i, n) {
		if (a[i] < N) {
			x.push_back(a[i]);
		} else {
			y.push_back(a[i]);
		}
	}

	int m = x.size();
	vector<set<ll>> dp(m + 1);
	vector<map<ll, int>> pre(m + 1);

	dp[0].insert(0);
	pre[0][0] = -1;
	rep (i, m) {
		for (auto u : dp[i]) {
			if (!dp[i + 1].count(u)) {
				dp[i + 1].insert(u);
				pre[i + 1][u] = u;
			}
			if (!dp[i + 1].count(u + x[i])) {
				dp[i + 1].insert(u + x[i]);
				pre[i + 1][u + x[i]] = u;
			}
		}
	}

	map<ll, string> mp;
	rep (i, 1 << y.size()) {
		ll sum = 0;
		string s;
		rep (j, y.size()) {
			if (i & 1 << j) {
				sum += y[j];
				s += "o";
			} else {
				s += "x";
			}
			if (sum >= 1e13) goto loopend;
		}
		mp[sum] = s;
		loopend:;
	}

	for (auto u : dp[m]) {
		if (mp.count(X - u)) {
			string ans;
			int curr = u;
			int i = m;
			while (i > 0) {
				int next = pre[i][curr];
				if (next < curr) {
					ans = "o" + ans;
				} else {
					ans = "x" + ans;
				}
				curr = next;
				i--;
			}
			ans += mp[X - u];
			string ans2 = ans;
			rep (i, n) ans2[ai[i].second] = ans[i];
			cout << ans2 << endl;
			return 0;
		}
	}
	cout << "No" << endl;
	return 0;
}