n, x = map(int, input().split())
a = list(map(int, input().split()))
total = sum(a)

if total < x:
    print("No")
elif total == x:
    print('o' * n)
else:
    # Initialize DP list to track possible sums at each step
    dp = [set() for _ in range(n + 1)]
    dp[0].add(0)
    for i in range(n):
        current = a[i]
        dp[i+1] = dp[i].copy()
        for s in dp[i]:
            if s + current <= x:
                dp[i+1].add(s + current)
    
    if x not in dp[n]:
        print("No")
    else:
        selected = set()
        remaining = x
        # Backtrack to find selected elements
        for i in reversed(range(n)):
            num = a[i]
            if remaining >= num and (remaining - num) in dp[i]:
                selected.add(i)
                remaining -= num
        # Generate the result string
        result = ['o' if i in selected else 'x' for i in range(n)]
        print(''.join(result))