#include <string>
#include <vector>
#include <algorithm>
#include <numeric>
#include <set>
#include <map>
#include <queue>
#include <iostream>
#include <sstream>
#include <cstdio>
#include <cmath>
#include <ctime>
#include <cstring>
#include <cctype>
#include <cassert>
#include <limits>
#include <functional>
#include <bitset>
#define rep(i,n) for(int (i)=0;(i)<(int)(n);++(i))
#define rer(i,l,u) for(int (i)=(int)(l);(i)<=(int)(u);++(i))
#define reu(i,l,u) for(int (i)=(int)(l);(i)<(int)(u);++(i))
#if defined(_MSC_VER) || __cplusplus > 199711L
#define aut(r,v) auto r = (v)
#else
#define aut(r,v) __typeof(v) r = (v)
#endif
#define each(it,o) for(aut(it, (o).begin()); it != (o).end(); ++ it)
#define all(o) (o).begin(), (o).end()
#define pb(x) push_back(x)
#define mp(x,y) make_pair((x),(y))
#define mset(m,v) memset(m,v,sizeof(m))
#define INF 0x3f3f3f3f
#define INFL 0x3f3f3f3f3f3f3f3fLL
using namespace std;
typedef vector<int> vi; typedef pair<int, int> pii; typedef vector<pair<int, int> > vpii; typedef long long ll;
template<typename T, typename U> inline void amin(T &x, U y) { if(y < x) x = y; }
template<typename T, typename U> inline void amax(T &x, U y) { if(x < y) x = y; }

int main() {
	int N; long long X;
	while(~scanf("%d%lld", &N, &X)) {
		vector<int> A(N);
		for(int i = 0; i < N; ++ i)
			scanf("%d", &A[i]);
		const int P = 30000;
		typedef bitset<100> Bitset;
		vector<Bitset> dp(P * N + 1);
		dp[0].set(N);
		int totalSmall = 0;
		rep(i, N) {
			int a = A[i];
			if(a >= P) continue;
			rer(j, 0, totalSmall) if(!dp[j].none() && dp[j + a].none())
				(dp[j + a] = dp[j]).set(i);
			totalSmall += a;
		}
		vpii bigs;
		rep(i, N) if(A[i] >= P) {
			bigs.push_back(mp(i, A[i]));
		}
		int B = (int)bigs.size();
		Bitset ansset;
		rep(i, 1 << B) {
			ll sum = 0;
			rep(j, B) if(i >> j & 1)
				sum += bigs[j].second;
			if(sum <= X && X - sum <= totalSmall) {
				const Bitset &t = dp[(int)(X - sum)];
				if(!t.none()) {
					ansset = t;
					rep(j, B) if(i >> j & 1)
						ansset.set(bigs[j].first);
					break;
				}
			}
		}
		if(ansset.none()) {
			puts("No");
		} else {
			rep(i, N)
				putchar(ansset[i] ? 'o' : 'x');
			puts("");
		}
	}
	return 0;
}