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

small = []
big = []
for i, a in enumerate(A):
    if a <= 10 ** 5:
        small.append(i)
    else:
        big.append(i)

M = len(small)
W = sum(A[i] for i in small)
dp = [[0] * (W + 1) for _ in range(M + 1)]
dp[0][0] = 1
for i in range(M):
    for j in range(W + 1 - A[small[i]]):
        if dp[i][j]:
            dp[i+1][j] = 1
            dp[i+1][j + A[small[i]]] = 1

K = len(big)
for S in range(1 << K):
    tot = 0
    for i in range(K):
        if (S >> i) & 1:
            tot += A[big[i]]
    Y = X - tot
    if Y > W:
        continue
    if dp[M][Y]:
        ans = ["x"] * N
        for i in range(K):
            if (S >> i) & 1:
                ans[big[i]] = "o"

        p, q = M, Y
        for _ in range(M):
            if dp[p-1][Y]:
                p -= 1
            elif dp[p-1][Y - A[small[p-1]]]:
                p -= 1
                Y -= A[small[p]]
                ans[small[p]] = "o"
            else:
                assert(0)
        print("".join(ans))
        exit()
print("No")