#include <iostream>
#include <sstream>
#include <fstream>
#include <string>
#include <vector>
#include <deque>
#include <queue>
#include <stack>
#include <set>
#include <map>
#include <algorithm>
#include <functional>
#include <utility>
#include <bitset>
#include <cmath>
#include <cstdlib>
#include <ctime>
#include <cstdio>

using namespace std;

#define REP(i,n) for((i)=0;(i)<(int)(n);(i)++)
#define snuke(c,itr) for(__typeof((c).begin()) itr=(c).begin();itr!=(c).end();itr++)

typedef long long ll;

int N,K;
int a[110];
vector <pair <int, int> > v; // a[i], id
bitset <800010> dp[90];

bool found = false;
bool ans[110];
bool ans2[110];

void check(ll X){
	int i;
	
	if(X < 0 || X >= 8000010 || found) return;
	
	dp[0].reset();
	dp[0][0] = true;
	REP(i,N-K) dp[i+1] = ((dp[i] << a[v[i].second]) | dp[i]);
	
	if(!dp[N-K][X]) return;
	
	found = true;
	for(i=N-K-1;i>=0;i--){
		int id = v[i].second;
		if(a[id] <= X && dp[i][X-a[id]]){
			ans[id] = true;
			X -= a[id];
		} else {
			ans[id] = false;
		}
	}
	
	REP(i,N) ans2[i] = ans[i];
}

void dfs(int pos, ll X){
	if(pos == N-K){
		check(X);
		return;
	}
	
	int id = v[pos-1].second;
	ans[id] = false;
	dfs(pos-1, X);
	ans[id] = true;
	dfs(pos-1, X-a[id]);
}

int main(void){
	int i;
	
	ll X;
	cin >> N >> X;
	REP(i,N) cin >> a[i];
	
	REP(i,N) v.push_back(make_pair(a[i], i));
	sort(v.begin(),v.end());
	
	K = min(N, 20);
	dfs(N, X);
	
	if(!found){
		cout << "No" << endl;
	} else {
		string s;
		REP(i,N) s += (ans2[i] ? 'o' : 'x');
		cout << s << endl;
	}
	
	return 0;
}