def main():
    import sys
    input = sys.stdin.read().split()
    idx = 0
    N = int(input[idx])
    idx += 1
    X = int(input[idx])
    idx += 1
    A = list(map(int, input[idx:idx + N]))
    idx += N

    total_sum = sum(A)
    if total_sum < X:
        print("No")
        return
    if total_sum == X:
        print('o' * N)
        return

    dp = {0: 0}
    for i in range(N):
        a = A[i]
        current_sums = list(dp.keys())
        for s in current_sums:
            new_sum = s + a
            if new_sum > X:
                continue
            new_mask = dp[s] | (1 << i)
            if new_sum in dp:
                if (dp[new_sum] & (1 << i)) == 0:
                    dp[new_sum] = new_mask
            else:
                dp[new_sum] = new_mask
        if X in dp:
            mask = dp[X]
            res = ['x'] * N
            for j in range(N):
                if (mask >> j) & 1:
                    res[j] = 'o'
            print(''.join(res))
            return

    print("No")

if __name__ == "__main__":
    main()