#include <bits/stdc++.h>
#define rep(i,n) for(int i=0;i<n;++i)
using namespace std;
using ll=long long ;
using pii=pair<int,int>;

int n;
ll x;
pii a[110];
map<ll,ll> dp[110];

void output(string arg){
	string ans=arg;
	rep(i,n) ans[a[i].second]=arg[i];
	cout << ans << endl;
	return ;
}

int main(void){
	cin >> n >> x;
	const int m=min(n,20);
	const int offset=n-m;
	
	rep(i,n) cin >> a[i].first,a[i].second=i;
	sort(a,a+n);

	dp[0][0]=-1LL;
	rep(i,offset){
		for(auto &it:dp[i]){
			ll cur=it.first;
			dp[i+1][cur]=cur;
			dp[i+1][cur+a[i].first]=cur;
		}		
	}

	rep(mask,1<<m){
		ll cur=0LL;
		string ans="";
		rep(i,m){
			if(mask&(1<<i)){
				cur+=a[i+offset].first;
				ans+="o";
			}else{
				ans+="x";
			}
		}

		if(x<cur) continue;
		cur=x-cur;

		if(dp[offset].find(cur)!=dp[offset].end()){
			reverse(ans.begin(),ans.end());	
			for(int i=offset;i>0;--i){
				if(cur!=dp[i][cur]){
					ans+="o";
				}else{
					ans+="x";
				}
				cur=dp[i][cur];
			}
			assert(cur==0LL);
			reverse(ans.begin(),ans.end());
			output(ans);
			return 0;
		}
	}
	puts("No");
	return 0;
}