# 解説を見た。
# 最初、bit DPで解けるのでは？　と思って制約をちゃんと見なかったのは愚か。

import sys
input = sys.stdin.readline

N,X=list(map(int,input().split()))
A=list(map(int,input().split()))

B=[(A[i],i) for i in range(N)]
B.sort(reverse=True)

C=B[:20]
D=B[20:]

NOW=1

DP=[1]
SUM=0
for a,_ in D:
    NOW=NOW|(NOW<<a)
    DP.append(NOW)
    SUM+=a

for i in range(1<<len(C)):
    score=0
    ANS=[0]*N
    for j in range(len(C)):
        if i & (1<<j) != 0:
            score+=C[j][0]
            ANS[C[j][1]]=1

    #print(i,score)
    if score>X:
        continue
    if X-score>SUM:
        continue

    if (1<<(X-score))&DP[-1]!=0:
        NOW=(1<<(X-score))

        for i in range(len(D)-1,-1,-1):
            a=D[i][0]
            ind=D[i][1]
            if DP[i] & (NOW>>a) != 0:
                ANS[ind]=1
                NOW>>=a

        #print(ANS)
        for j in range(len(ANS)):
            if ANS[j]==1:
                ANS[j]="o"
            else:
                ANS[j]="x"

        print("".join(ANS))
        exit()

print("No")