# include "bits/stdc++.h"
using namespace std;
using LL = long long;
using ULL = unsigned long long;
const double PI = acos(-1);
template<class T>constexpr T INF() { return ::std::numeric_limits<T>::max(); }
template<class T>constexpr T HINF() { return INF<T>() / 2; }
template <typename T_char>T_char TL(T_char cX) { return tolower(cX); };
template <typename T_char>T_char TU(T_char cX) { return toupper(cX); };
const int vy[] = { -1, -1, -1, 0, 1, 1, 1, 0 }, vx[] = { -1, 0, 1, 1, 1, 0, -1, -1 };
const int dx[4] = { -1,0,1,0 }, dy[4] = { 0,-1,0,1 };
int popcnt(unsigned long long n) { int cnt = 0; for (int i = 0; i < 64; i++)if ((n >> i) & 1)cnt++; return cnt; }
int d_sum(LL n) { int ret = 0; while (n > 0) { ret += n % 10; n /= 10; }return ret; }
int d_cnt(LL n) { int ret = 0; while (n > 0) { ret++; n /= 10; }return ret; }
LL gcd(LL a, LL b) { if (b == 0)return a; return gcd(b, a%b); };
LL lcm(LL a, LL b) { LL g = gcd(a, b); return a / g*b; };
# define ALL(qpqpq)           (qpqpq).begin(),(qpqpq).end()
# define UNIQUE(wpwpw)        (wpwpw).erase(unique(ALL((wpwpw))),(wpwpw).end())
# define LOWER(epepe)         transform(ALL((epepe)),(epepe).begin(),TL<char>)
# define UPPER(rprpr)         transform(ALL((rprpr)),(rprpr).begin(),TU<char>)
# define FOR(i,tptpt,ypypy)   for(LL i=(tptpt);i<(ypypy);i++)
# define REP(i,upupu)         FOR(i,0,upupu)
# define INIT                 std::ios::sync_with_stdio(false);std::cin.tie(0)
# pragma warning(disable:4996)

LL n, x;
vector<pair<LL, int>> a;
bool dp[10000000];
int last[10000000];
bool isok[101];
int main() {
	cin >> n >> x;
	a.resize(n);
	REP(i, n) {
		cin >> a[i].first;
		a[i].second = i;
	}
	sort(ALL(a));
	reverse(ALL(a));
	dp[0] = true;
	for (int i = 20; i < n; i++) {
		for (LL j = 10000000; j >= 0; j--) {
			if (j - a[i].first >= 0 && dp[j - a[i].first]) {
				dp[j] = true;
				last[j] = i;
			}
		}
	}
	REP(i, (1 << min(n, 20LL))) {
		LL num = 0;
		REP(j, min(n, 20LL)) {
			if ((1 << j)&i)num += a[j].first;
		}
		if (x - num >= 0 && x - num < 10000000 && dp[x - num]) {
			int cnt = 0;
			LL num2 = i;
			while (num2 > 0) {
				if (num2 % 2)isok[a[cnt].second] = true;
				num2 /= 2;
				cnt++;
			}
			num2 = x - num;
			while (num2 > 0) {
				isok[a[last[num2]].second] = true;
				num2 -= a[last[num2]].first;
			}
			REP(j, n) {
				cout << (isok[j] ? 'o' : 'x');
			}
			cout << endl;
			//system("pause");
			return 0;
		}
	}
	cout << "No" << endl;
	//system("pause");
}