#include<bits/stdc++.h>
using namespace std;

#define int long long
typedef pair<int,int>pint;
typedef vector<int>vint;
typedef vector<pint>vpint;
#define pb push_back
#define mp make_pair
#define fi first
#define se second
#define all(v) (v).begin(),(v).end()
#define rep(i,n) for(int i=0;i<(n);i++)
#define reps(i,f,n) for(int i=(f);i<(n);i++)
#define each(it,v) for(__typeof((v).begin()) it=(v).begin();it!=(v).end();it++)
template<class T,class U>inline void chmin(T &t,U f){if(t>f)t=f;}
template<class T,class U>inline void chmax(T &t,U f){if(t<f)t=f;}

int N,X;
int A[100];

const int lim=500000;
int dp[111][lim+1];

signed main(){
    cin>>N>>X;
    rep(i,N)cin>>A[i];

    memset(dp,-1,sizeof(dp));

    vpint vec;
    rep(i,N)vec.pb(pint(A[i],i));
    sort(all(vec));reverse(all(vec));
    bool big[100]={};
    rep(i,min(N,20ll))big[vec[i].se]=true;

    dp[0][0]=0;
    vint lis;
    rep(i,N){
        if(!big[i])dp[i+1][A[i]]=i;
        for(int j=0;j<=lim;j++){
            if(dp[i][j]<0)continue;
            if(!big[i]&&j+A[i]<=lim)dp[i+1][j+A[i]]=1;
            dp[i+1][j]=0;
        }
        if(big[i])lis.pb(i);
    }

    rep(i,1<<lis.size()){
        int s=0;
        rep(j,lis.size())if(i>>j&1)s+=A[lis[j]];
        if(s>X||X-s>=lim||dp[N][X-s]<0)continue;
        bool used[100]={};
        rep(j,lis.size())if(i>>j&1)used[lis[j]]=true;
        int cur=X-s;
        for(int j=N;j>0;j--){
            if(dp[j][cur]==1){
                used[j-1]=true;
                cur-=A[j-1];
            }
        }

        rep(j,N){
            if(used[j])cout<<'o';
            else cout<<'x';
        }
        cout<<endl;
        return 0;
    }

    cout<<"No"<<endl;
    return 0;
}