import sys
readline=sys.stdin.readline

N,X=map(int,readline().split())
A=list(map(int,readline().split()))
M=10**5
idx0=[]
idx1=[]
for i in range(N):
    if A[i]>=M:
        idx0.append(i)
    else:
        idx1.append(i)
le0=len(idx0)
le1=len(idx1)
dp=[0]*(le1+1)
dp[0]|=1
for i in range(1,le1+1):
    dp[i]=dp[i-1]|dp[i-1]<<A[idx1[i-1]]
for bit in range(1<<le0):
    s=sum(A[idx0[i]] for i in range(le0) if bit&1<<i)
    if X-s>=0 and dp[le1]&1<<X-s:
        ans_lst=[None]*N
        for i in range(le0):
            if bit&1<<i:
                ans_lst[idx0[i]]="o"
            else:
                ans_lst[idx0[i]]="x"
        s=X-s
        for i in range(le1-1,-1,-1):
            if dp[i]&1<<s:
                ans_lst[idx1[i]]="x"
            else:
                ans_lst[idx1[i]]="o"
                s-=A[i]
        print(*ans_lst,sep="")
        break
else:
    print("No")