#include <bits/stdc++.h>
#define rep(i,n) for(int i=0;i<(int)(n);i++)
#define rep1(i,n) for(int i=1;i<=(int)(n);i++)
#define all(c) c.begin(),c.end()
#define pb push_back
#define fs first
#define sc second
#define show(x) cout << #x << " = " << x << endl
#define chmin(x,y) x=min(x,y)
#define chmax(x,y) x=max(x,y)
using namespace std;
typedef long long ll;
int N;
ll X,a[100];
vector<int> ls,ss;		//large,small
typedef pair<ll,int> P;
set<P> st;
bool dp[101][2227601];
int main(){
	cin>>N>>X;
	rep(i,N) cin>>a[i];
	rep(i,N){
		if(a[i]>=22276) ls.pb(i);
		else ss.pb(i);
	}
	int K=ls.size();
	rep(i,1<<K){
		ll S=0;
		rep(j,K) if((i>>j)&1) S+=a[ls[j]];
		st.insert(P(S,i));
	}
	int B=ss.size();
	int S=0;
	dp[0][0]=1;
	rep(i,B){
		rep(j,S+1){
			if(dp[i][j]) dp[i+1][j+a[ss[i]]]=1,dp[i+1][j]=1;
		}
		S+=a[ss[i]];
	}
	rep(j,S+1) if(dp[B][j]){
		auto it=st.lower_bound(P(X-j,0));
		if(it==st.end()||it->fs!=X-j) continue;
		string ans(N,'x');
		int s=j;
		for(int i=B-1;i>=0;i--){
			if(!dp[i][s]) s-=a[ss[i]],ans[ss[i]]='o';
		}
		int id=it->sc;
		rep(i,K) if((id>>i)&1) ans[ls[i]]='o';
		cout<<ans<<endl;
		return 0;
	}
	puts("No");
}